From fff4880c4f7d3dcbe1e9e1360eb2cfa4a1adba4d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dominik=20Madar=C3=A1sz?= <zaklaus@outlook.com>
Date: Sat, 23 Sep 2023 20:53:25 +0200
Subject: [PATCH] render: finish up phong shading

---
 demos/99-material.c                           |   3 +-
 engine/art/shaders/fs_32_4_model.glsl         |  65 ++++++++---
 .../shaders/vs_323444143_16_332_model.glsl    |   3 +-
 engine/art/shaders/vs_332_32.glsl             |   5 +-
 engine/bind/v4k.lua                           |  29 +++--
 engine/joint/v4k.h                            | 104 ++++++++++++++----
 engine/split/v4k_render.c                     |  29 ++++-
 engine/split/v4k_render.h                     |   8 ++
 engine/split/v4k_scene.c                      |  46 ++++++--
 engine/split/v4k_scene.h                      |  21 ++--
 engine/v4k.c                                  |  75 ++++++++++---
 engine/v4k.h                                  |  29 +++--
 12 files changed, 318 insertions(+), 99 deletions(-)

diff --git a/demos/99-material.c b/demos/99-material.c
index 74c08ba..0fd5413 100644
--- a/demos/99-material.c
+++ b/demos/99-material.c
@@ -41,7 +41,7 @@ int main() {
 
     // create point light
     light_t* l = scene_spawn_light();
-    light_type(l, LIGHT_POINT);
+    light_type(l, LIGHT_SPOT);
 
     while(window_swap() && !input(KEY_ESC)) {
         // draw environment
@@ -53,6 +53,7 @@ int main() {
 
         // update light position
         light_teleport(l, cam.position);
+        light_dir(l, cam.look);
 
         // draw scene
         scene_render(SCENE_FOREGROUND|SCENE_BACKGROUND|SCENE_UPDATE_SH_COEF);
diff --git a/engine/art/shaders/fs_32_4_model.glsl b/engine/art/shaders/fs_32_4_model.glsl
index af08e7f..e90bf22 100644
--- a/engine/art/shaders/fs_32_4_model.glsl
+++ b/engine/art/shaders/fs_32_4_model.glsl
@@ -7,6 +7,7 @@ uniform bool u_matcaps = false;
 uniform vec4 u_diffuse = vec4(1.0,1.0,1.0,1.0);
 
 in vec3 v_position;
+in vec3 v_position_ws;
 #ifdef RIM
 uniform mat4 M; // RIM
 uniform vec3 u_rimcolor = vec3(0.2,0.2,0.2);
@@ -28,14 +29,25 @@ vec4 shadowing() {
 return shadowmap(vpeye, vneye, v_texcoord, sc);
 }
 
+uniform vec3 u_cam_pos;
+uniform vec3 u_cam_dir;
+
 uniform int u_num_lights;
 
 struct light_t {
     int type;
-    vec3 color;
+    vec3 diffuse;
+    vec3 specular;
+    vec3 ambient;
     vec3 pos;
     vec3 dir;
-    float radius;
+    float innerCone;
+    float outerCone;
+
+    // falloff
+    float constant;
+    float linear;
+    float quadratic;
 };
 
 #define MAX_LIGHTS 16
@@ -45,27 +57,53 @@ const int LIGHT_SPOT = 2;
 
 uniform light_t u_lights[MAX_LIGHTS];
 
-vec3 calculate_light(light_t l, vec3 normal, vec3 fragPos, vec3 viewDir) {
+#ifdef SHADING_PHONG
+vec3 shading_phong(light_t l) {
     vec3 lightDir;
     float attenuation = 1.0;
 
     if (l.type == LIGHT_DIRECTIONAL) {
         lightDir = normalize(-l.dir);
     } else if (l.type == LIGHT_POINT) {
-        vec3 toLight = l.pos - fragPos;
+        vec3 toLight = l.pos - v_position_ws;
         lightDir = normalize(toLight);
         float distance = length(toLight);
-        float factor = distance / (l.radius*l.radius);
-        attenuation = clamp(1.0 - factor, 0.0, 1.0);
+        attenuation = 1.0 / (l.constant + l.linear * distance + l.quadratic * (distance * distance));
+    } else if (l.type == LIGHT_SPOT) {
+        vec3 toLight = l.pos - v_position_ws;
+        lightDir = normalize(toLight);
+        float distance = length(toLight);
+        attenuation = 1.0 / (l.constant + l.linear * distance + l.quadratic * (distance * distance));
+        
+        // Calculate spotlight effect
+        float angle = dot(l.dir, normalize(-lightDir));
+        if (angle > l.outerCone) {
+            float intensity = (angle-l.outerCone)/(l.innerCone-l.outerCone);
+            attenuation *= clamp(intensity, 0.0, 1.0);
+        } else {
+            attenuation = 0.0;
+        }
     }
 
-    float diff = max(dot(normal, lightDir), 0.0);
+    float diffuse = max(dot(v_normal, lightDir), 0.0);
 
-    // vec3 reflectDir = reflect(-lightDir, normal);
-    // float spec = pow(max(dot(viewDir, reflectDir), 0.0), 32);
-    // vec3 specular = spec * lightColor;
+    vec3 halfVec = normalize(lightDir + u_cam_dir);
+    float specular = pow(max(dot(v_normal, halfVec), 0.0), 32);
 
-    return (diff /* + specular */) * l.color;
+    return (attenuation*l.ambient + diffuse*attenuation*l.diffuse + specular*attenuation*l.specular);
+}
+#endif
+
+vec3 lighting() {
+    vec3 lit = vec3(0,0,0);
+#ifndef SHADING_NONE
+    for (int i=0; i<u_num_lights; i++) {
+    #ifdef SHADING_PHONG
+        lit += shading_phong(u_lights[i]);
+    #endif
+    }
+#endif
+    return lit;
 }
 
 void main() {
@@ -91,10 +129,7 @@ void main() {
     }
 
     // analytical lights (phong shading)
-    // @todo: support more shading models (blinn-phong, ue4 brdf, ...)
-    for (int i=0; i<u_num_lights; i++) {
-        lit += vec4(calculate_light(u_lights[i], n, v_position, /* @todo: push vdeye */ vec3(1.0,1.0,1.0)), 0.0);
-    }
+    lit += vec4(lighting(), 0.0);
 
     // base
     vec4 diffuse;
diff --git a/engine/art/shaders/vs_323444143_16_332_model.glsl b/engine/art/shaders/vs_323444143_16_332_model.glsl
index 88284a9..4ce7864 100644
--- a/engine/art/shaders/vs_323444143_16_332_model.glsl
+++ b/engine/art/shaders/vs_323444143_16_332_model.glsl
@@ -57,7 +57,7 @@ in float att_vertexindex; // for blendshapes
 in vec4 att_color;
 in vec3 att_bitangent; // @todo: remove? also, ass2iqe might output this
 out vec4 v_color;
-out vec3 v_position;
+out vec3 v_position, v_position_ws;
 out vec3 v_normal, v_normal_ws;
 out vec2 v_texcoord;
 
@@ -115,6 +115,7 @@ void main() {
         
         v_normal_ws = normalize(vec3(model * vec4(v_normal, 0.))); // normal to world/model space
         v_normal = normalize(v_normal);
+        v_position_ws = (att_instanced_matrix * vec4( objPos, 1.0 )).xyz;
         v_position = att_position;
         v_texcoord = att_texcoord;
         v_color = att_color;
diff --git a/engine/art/shaders/vs_332_32.glsl b/engine/art/shaders/vs_332_32.glsl
index d4b2c4a..151083d 100644
--- a/engine/art/shaders/vs_332_32.glsl
+++ b/engine/art/shaders/vs_332_32.glsl
@@ -6,11 +6,12 @@ in vec3 att_normal;
 in vec2 att_texcoord;
 in vec4 att_color;
 out vec4 v_color;
+out vec3 v_position;
+out vec3 v_position_ws;
 out vec3 v_normal;
 out vec3 v_normal_ws;
 out vec2 v_texcoord;
 
-
 // shadow
 uniform mat4 model, view, proj;
 uniform mat4 cameraToShadowProjector; // !VSMCUBE
@@ -26,6 +27,8 @@ void do_shadow() {
 
 void main() {
     gl_Position = u_mvp * vec4(att_position, 1.0);
+    v_position = att_position;
+    v_position_ws = vec3(model * vec4(att_position, 1.));
     v_normal = normalize(att_normal);
     v_normal_ws = normalize(vec3(model * vec4(att_normal, 0.))); // normal world/model space
     v_texcoord = att_texcoord;
diff --git a/engine/bind/v4k.lua b/engine/bind/v4k.lua
index 951d086..44d7396 100644
--- a/engine/bind/v4k.lua
+++ b/engine/bind/v4k.lua
@@ -1392,11 +1392,17 @@ ffi.cdef([[
 //lcpp INF [0000] vec3: macro name but used as C declaration in:API void object_scale(object_t *obj, vec3 sca);
 //lcpp INF [0000] vec3: macro name but used as C declaration in:STATIC void object_scale(object_t *obj, vec3 sca);
 //lcpp INF [0000] vec3: macro name but used as C declaration in: void object_scale(object_t *obj, vec3 sca);
-//lcpp INF [0000] vec3: macro name but used as C declaration in:vec3 color;
+//lcpp INF [0000] vec3: macro name but used as C declaration in:vec3 diffuse, specular, ambient;
 //lcpp INF [0000] vec3: macro name but used as C declaration in:vec3 pos, dir;
-//lcpp INF [0000] vec3: macro name but used as C declaration in:API void    light_color(light_t* l, vec3 color);
-//lcpp INF [0000] vec3: macro name but used as C declaration in:STATIC void    light_color(light_t* l, vec3 color);
-//lcpp INF [0000] vec3: macro name but used as C declaration in: void    light_color(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in:API void    light_diffuse(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in:STATIC void    light_diffuse(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in: void    light_diffuse(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in:API void    light_specular(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in:STATIC void    light_specular(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in: void    light_specular(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in:API void    light_ambient(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in:STATIC void    light_ambient(light_t* l, vec3 color);
+//lcpp INF [0000] vec3: macro name but used as C declaration in: void    light_ambient(light_t* l, vec3 color);
 //lcpp INF [0000] vec3: macro name but used as C declaration in:API void    light_teleport(light_t* l, vec3 pos);
 //lcpp INF [0000] vec3: macro name but used as C declaration in:STATIC void    light_teleport(light_t* l, vec3 pos);
 //lcpp INF [0000] vec3: macro name but used as C declaration in: void    light_teleport(light_t* l, vec3 pos);
@@ -2695,17 +2701,23 @@ LIGHT_CAST_SHADOWS = 1,
 };
 typedef struct light_t {
 char type;
-vec3 color;
+vec3 diffuse, specular, ambient;
 vec3 pos, dir;
-float radius;
+struct {
+float constant, linear, quadratic;
+} falloff;
+float innerCone, outerCone;
 bool cached;
 } light_t;
  light_t light();
  void    light_type(light_t* l, char type);
- void    light_color(light_t* l, vec3 color);
+ void    light_diffuse(light_t* l, vec3 color);
+ void    light_specular(light_t* l, vec3 color);
+ void    light_ambient(light_t* l, vec3 color);
  void    light_teleport(light_t* l, vec3 pos);
  void    light_dir(light_t* l, vec3 dir);
- void    light_radius(light_t* l, float radius);
+ void    light_falloff(light_t* l, float constant, float linear, float quadratic);
+ void    light_cone(light_t* l, float innerCone, float outerCone);
  void    light_update(unsigned num_lights, light_t *lv);
 enum SCENE_FLAGS {
 SCENE_WIREFRAME = 1,
@@ -2715,7 +2727,6 @@ SCENE_FOREGROUND = 8,
 SCENE_UPDATE_SH_COEF = 16,
 };
 typedef struct scene_t {
-handle program;
 object_t* objs;
 light_t* lights;
 skybox_t skybox;
diff --git a/engine/joint/v4k.h b/engine/joint/v4k.h
index 6a67411..7183959 100644
--- a/engine/joint/v4k.h
+++ b/engine/joint/v4k.h
@@ -16922,6 +16922,14 @@ enum MODEL_FLAGS {
     MODEL_RIMLIGHT = 16
 };
 
+//@todo: make this data-driven
+// enum SHADING_MODE {
+//     SHADING_NONE,
+//     SHADING_PHONG,
+//     SHADING_CARTOON,
+//     // SHADING_PBR,
+// };
+
 typedef struct model_t {
     struct iqm_t *iqm; // private
 
@@ -17164,21 +17172,28 @@ enum LIGHT_FLAGS {
 
 typedef struct light_t {
     char type;
-    vec3 color;
+    vec3 diffuse, specular, ambient;
     vec3 pos, dir;
-    float radius;
+    struct {
+        float constant, linear, quadratic;
+    } falloff;
+    float innerCone, outerCone;
+    //@todo: cookie, flare
+
+    // internals
     bool cached; //< used by scene to invalidate cached light data
-    //@todo: inner/outer cone, flags, cookie, flare
 } light_t;
 
 API light_t light();
 // API void    light_flags(int flags);
 API void    light_type(light_t* l, char type);
-API void    light_color(light_t* l, vec3 color);
+API void    light_diffuse(light_t* l, vec3 color);
+API void    light_specular(light_t* l, vec3 color);
+API void    light_ambient(light_t* l, vec3 color);
 API void    light_teleport(light_t* l, vec3 pos);
 API void    light_dir(light_t* l, vec3 dir);
-API void    light_radius(light_t* l, float radius);
-// API void    light_cone(light_t* l, float inner, float outer);
+API void    light_falloff(light_t* l, float constant, float linear, float quadratic);
+API void    light_cone(light_t* l, float innerCone, float outerCone);
 API void    light_update(unsigned num_lights, light_t *lv);
 
 // scene
@@ -17192,8 +17207,6 @@ enum SCENE_FLAGS {
 };
 
 typedef struct scene_t {
-    handle program;
-
     array(object_t) objs;
     array(light_t) lights;
 
@@ -343293,6 +343306,24 @@ void model_set_uniforms(model_t m, int shader, mat44 mv, mat44 proj, mat44 view,
         mat44 vp; multiply44x2(vp, proj, view);
         glUniformMatrix4fv( loc, 1, GL_FALSE, vp);
     }
+    if( (loc = glGetUniformLocation(shader, "u_cam_pos")) >= 0 ) {
+        vec3 pos = vec3(view[3], view[6], view[9]);
+        glUniform3fv( loc, 1, &pos.x );
+    }
+    else
+    if( (loc = glGetUniformLocation(shader, "cam_pos")) >= 0 ) {
+        vec3 pos = vec3(view[3], view[6], view[9]);
+        glUniform3fv( loc, 1, &pos.x );
+    }
+    if( (loc = glGetUniformLocation(shader, "u_cam_dir")) >= 0 ) {
+        vec3 dir = vec3(view[0], view[1], view[2]);
+        glUniform3fv( loc, 1, &dir.x );
+    }
+    else
+    if( (loc = glGetUniformLocation(shader, "cam_dir")) >= 0 ) {
+        vec3 dir = vec3(view[0], view[1], view[2]);
+        glUniform3fv( loc, 1, &dir.x );
+    }
 #if 0
     // @todo: mat44 projview (useful?)
 #endif
@@ -343729,13 +343760,14 @@ model_t model_from_mem(const void *mem, int len, int flags) {
     model_t m = {0};
 
     const char *ptr = (const char *)mem;
-    static int shaderprog = -1;
-    if( shaderprog < 0 ) {
+    // can't cache shader programs since we enable features via flags here
+    // static int shaderprog = -1;
+    // if( shaderprog < 0 ) {
         const char *symbols[] = { "{{include-shadowmap}}", vfs_read("shaders/fs_0_0_shadowmap_lit.glsl") }; // #define RIM
-        shaderprog = shader(strlerp(1,symbols,vfs_read("shaders/vs_323444143_16_332_model.glsl")), strlerp(1,symbols,vfs_read("shaders/fs_32_4_model.glsl")), //fs,
+        int shaderprog = shader(strlerp(1,symbols,vfs_read("shaders/vs_323444143_16_332_model.glsl")), strlerp(1,symbols,vfs_read("shaders/fs_32_4_model.glsl")), //fs,
             "att_position,att_texcoord,att_normal,att_tangent,att_instanced_matrix,,,,att_indexes,att_weights,att_vertexindex,att_color,att_bitangent","fragColor",
-            (flags&MODEL_RIMLIGHT)?"RIM":NULL);
-    }
+            va("SHADING_PHONG,%s", (flags&MODEL_RIMLIGHT)?"RIM":""));
+    // }
 
     iqm_t *q = CALLOC(1, sizeof(iqm_t));
     program = shaderprog;
@@ -345198,9 +345230,13 @@ void object_billboard(object_t *obj, unsigned mode) {
 
 light_t light() {
     light_t l = {0};
-    l.color = vec3(1,1,1);
-    l.radius = 2.5f;
+    l.diffuse = vec3(1,1,1);
     l.dir = vec3(1,-1,-1);
+    l.falloff.constant = 1.0f;
+    l.falloff.linear = 0.09f;
+    l.falloff.quadratic = 0.0032f;
+    l.innerCone = 0.9f; // 25 deg
+    l.outerCone = 0.85f; // 31 deg
 
     return l;
 }
@@ -345210,9 +345246,19 @@ void light_type(light_t* l, char type) {
     l->type = type;
 }
 
-void light_color(light_t* l, vec3 color) {
+void light_diffuse(light_t* l, vec3 color) {
     l->cached = 0;
-    l->color = color;
+    l->diffuse = color;
+}
+
+void light_specular(light_t* l, vec3 color) {
+    l->cached = 0;
+    l->specular = color;
+}
+
+void light_ambient(light_t* l, vec3 color) {
+    l->cached = 0;
+    l->ambient = color;
 }
 
 void light_teleport(light_t* l, vec3 pos) {
@@ -345225,9 +345271,16 @@ void light_dir(light_t* l, vec3 dir) {
     l->dir = dir;
 }
 
-void light_radius(light_t* l, float radius) {
+void light_falloff(light_t* l, float constant, float linear, float quadratic) {
     l->cached = 0;
-    l->radius = radius;
+    l->falloff.constant = constant;
+    l->falloff.linear = linear;
+    l->falloff.quadratic = quadratic;
+}
+
+void light_cone(light_t* l, float innerCone, float outerCone) {
+    l->innerCone = acos(innerCone);
+    l->outerCone = acos(outerCone);
 }
 
 void light_update(unsigned num_lights, light_t *lv) {
@@ -345236,9 +345289,16 @@ void light_update(unsigned num_lights, light_t *lv) {
     for (unsigned i=0; i < num_lights; ++i) {
         lv[i].cached = 1;
         shader_int(va("u_lights[%d].type", i), lv[i].type);
-        shader_vec3(va("u_lights[%d].color", i), lv[i].color);
         shader_vec3(va("u_lights[%d].pos", i), lv[i].pos);
         shader_vec3(va("u_lights[%d].dir", i), lv[i].dir);
+        shader_vec3(va("u_lights[%d].diffuse", i), lv[i].diffuse);
+        shader_vec3(va("u_lights[%d].specular", i), lv[i].specular);
+        shader_vec3(va("u_lights[%d].ambient", i), lv[i].ambient);
+        shader_float(va("u_lights[%d].constant", i), lv[i].falloff.constant);
+        shader_float(va("u_lights[%d].linear", i), lv[i].falloff.linear);
+        shader_float(va("u_lights[%d].quadratic", i), lv[i].falloff.quadratic);
+        shader_float(va("u_lights[%d].innerCone", i), lv[i].innerCone);
+        shader_float(va("u_lights[%d].outerCone", i), lv[i].outerCone);
     }
 }
 
@@ -345259,8 +345319,6 @@ scene_t* scene_get_active() {
 
 scene_t* scene_push() {
     scene_t *s = REALLOC(0, sizeof(scene_t)), clear = {0}; *s = clear;
-    const char *symbols[] = { "{{include-shadowmap}}", vfs_read("shaders/fs_0_0_shadowmap_lit.glsl") };
-    s->program = shader(strlerp(1, symbols, vfs_read("shaders/vs_332_32.glsl")), strlerp(1, symbols, vfs_read("shaders/fs_32_4_model.glsl")), "att_position,att_normal,att_texcoord,att_color", "fragcolor", NULL);
     s->skybox = skybox(NULL, 0);
     array_push(scenes, s);
     last_scene = s;
@@ -345371,7 +345429,6 @@ void scene_render(int flags) {
     glEnable(GL_DEPTH_TEST);
     glDepthFunc(GL_LESS);
     glActiveTexture(GL_TEXTURE0);
-    glUseProgram(last_scene->program);
 
     if(flags & SCENE_BACKGROUND) {
         if(last_scene->skybox.program) {
@@ -345392,7 +345449,6 @@ void scene_render(int flags) {
 
     glDepthFunc(GL_LESS);
     glActiveTexture(GL_TEXTURE0);
-//  glUseProgram(last_scene->program);
 
     // @fixme: CW ok for one-sided rendering. CCW ok for FXs. we need both
     (flags & SCENE_CULLFACE ? glEnable : glDisable)(GL_CULL_FACE); glCullFace(GL_BACK); glFrontFace(GL_CCW);
diff --git a/engine/split/v4k_render.c b/engine/split/v4k_render.c
index d15ad23..4329f23 100644
--- a/engine/split/v4k_render.c
+++ b/engine/split/v4k_render.c
@@ -3683,6 +3683,24 @@ void model_set_uniforms(model_t m, int shader, mat44 mv, mat44 proj, mat44 view,
         mat44 vp; multiply44x2(vp, proj, view);
         glUniformMatrix4fv( loc, 1, GL_FALSE, vp);
     }
+    if( (loc = glGetUniformLocation(shader, "u_cam_pos")) >= 0 ) {
+        vec3 pos = vec3(view[3], view[6], view[9]);
+        glUniform3fv( loc, 1, &pos.x );
+    }
+    else
+    if( (loc = glGetUniformLocation(shader, "cam_pos")) >= 0 ) {
+        vec3 pos = vec3(view[3], view[6], view[9]);
+        glUniform3fv( loc, 1, &pos.x );
+    }
+    if( (loc = glGetUniformLocation(shader, "u_cam_dir")) >= 0 ) {
+        vec3 dir = vec3(view[0], view[1], view[2]);
+        glUniform3fv( loc, 1, &dir.x );
+    }
+    else
+    if( (loc = glGetUniformLocation(shader, "cam_dir")) >= 0 ) {
+        vec3 dir = vec3(view[0], view[1], view[2]);
+        glUniform3fv( loc, 1, &dir.x );
+    }
 #if 0
     // @todo: mat44 projview (useful?)
 #endif
@@ -4119,13 +4137,14 @@ model_t model_from_mem(const void *mem, int len, int flags) {
     model_t m = {0};
 
     const char *ptr = (const char *)mem;
-    static int shaderprog = -1;
-    if( shaderprog < 0 ) {
+    // can't cache shader programs since we enable features via flags here
+    // static int shaderprog = -1;
+    // if( shaderprog < 0 ) {
         const char *symbols[] = { "{{include-shadowmap}}", vfs_read("shaders/fs_0_0_shadowmap_lit.glsl") }; // #define RIM
-        shaderprog = shader(strlerp(1,symbols,vfs_read("shaders/vs_323444143_16_332_model.glsl")), strlerp(1,symbols,vfs_read("shaders/fs_32_4_model.glsl")), //fs,
+        int shaderprog = shader(strlerp(1,symbols,vfs_read("shaders/vs_323444143_16_332_model.glsl")), strlerp(1,symbols,vfs_read("shaders/fs_32_4_model.glsl")), //fs,
             "att_position,att_texcoord,att_normal,att_tangent,att_instanced_matrix,,,,att_indexes,att_weights,att_vertexindex,att_color,att_bitangent","fragColor",
-            (flags&MODEL_RIMLIGHT)?"RIM":NULL);
-    }
+            va("SHADING_PHONG,%s", (flags&MODEL_RIMLIGHT)?"RIM":""));
+    // }
 
     iqm_t *q = CALLOC(1, sizeof(iqm_t));
     program = shaderprog;
diff --git a/engine/split/v4k_render.h b/engine/split/v4k_render.h
index 0bc4afb..6eb3744 100644
--- a/engine/split/v4k_render.h
+++ b/engine/split/v4k_render.h
@@ -572,6 +572,14 @@ enum MODEL_FLAGS {
     MODEL_RIMLIGHT = 16
 };
 
+//@todo: make this data-driven
+// enum SHADING_MODE {
+//     SHADING_NONE,
+//     SHADING_PHONG,
+//     SHADING_CARTOON,
+//     // SHADING_PBR,
+// };
+
 typedef struct model_t {
     struct iqm_t *iqm; // private
 
diff --git a/engine/split/v4k_scene.c b/engine/split/v4k_scene.c
index a272545..ee8e6c9 100644
--- a/engine/split/v4k_scene.c
+++ b/engine/split/v4k_scene.c
@@ -243,9 +243,13 @@ void object_billboard(object_t *obj, unsigned mode) {
 
 light_t light() {
     light_t l = {0};
-    l.color = vec3(1,1,1);
-    l.radius = 2.5f;
+    l.diffuse = vec3(1,1,1);
     l.dir = vec3(1,-1,-1);
+    l.falloff.constant = 1.0f;
+    l.falloff.linear = 0.09f;
+    l.falloff.quadratic = 0.0032f;
+    l.innerCone = 0.9f; // 25 deg
+    l.outerCone = 0.85f; // 31 deg
 
     return l;
 }
@@ -255,9 +259,19 @@ void light_type(light_t* l, char type) {
     l->type = type;
 }
 
-void light_color(light_t* l, vec3 color) {
+void light_diffuse(light_t* l, vec3 color) {
     l->cached = 0;
-    l->color = color;
+    l->diffuse = color;
+}
+
+void light_specular(light_t* l, vec3 color) {
+    l->cached = 0;
+    l->specular = color;
+}
+
+void light_ambient(light_t* l, vec3 color) {
+    l->cached = 0;
+    l->ambient = color;
 }
 
 void light_teleport(light_t* l, vec3 pos) {
@@ -270,9 +284,16 @@ void light_dir(light_t* l, vec3 dir) {
     l->dir = dir;
 }
 
-void light_radius(light_t* l, float radius) {
+void light_falloff(light_t* l, float constant, float linear, float quadratic) {
     l->cached = 0;
-    l->radius = radius;
+    l->falloff.constant = constant;
+    l->falloff.linear = linear;
+    l->falloff.quadratic = quadratic;
+}
+
+void light_cone(light_t* l, float innerCone, float outerCone) {
+    l->innerCone = acos(innerCone);
+    l->outerCone = acos(outerCone);
 }
 
 void light_update(unsigned num_lights, light_t *lv) {
@@ -281,9 +302,16 @@ void light_update(unsigned num_lights, light_t *lv) {
     for (unsigned i=0; i < num_lights; ++i) {
         lv[i].cached = 1;
         shader_int(va("u_lights[%d].type", i), lv[i].type);
-        shader_vec3(va("u_lights[%d].color", i), lv[i].color);
         shader_vec3(va("u_lights[%d].pos", i), lv[i].pos);
         shader_vec3(va("u_lights[%d].dir", i), lv[i].dir);
+        shader_vec3(va("u_lights[%d].diffuse", i), lv[i].diffuse);
+        shader_vec3(va("u_lights[%d].specular", i), lv[i].specular);
+        shader_vec3(va("u_lights[%d].ambient", i), lv[i].ambient);
+        shader_float(va("u_lights[%d].constant", i), lv[i].falloff.constant);
+        shader_float(va("u_lights[%d].linear", i), lv[i].falloff.linear);
+        shader_float(va("u_lights[%d].quadratic", i), lv[i].falloff.quadratic);
+        shader_float(va("u_lights[%d].innerCone", i), lv[i].innerCone);
+        shader_float(va("u_lights[%d].outerCone", i), lv[i].outerCone);
     }
 }
 
@@ -304,8 +332,6 @@ scene_t* scene_get_active() {
 
 scene_t* scene_push() {
     scene_t *s = REALLOC(0, sizeof(scene_t)), clear = {0}; *s = clear;
-    const char *symbols[] = { "{{include-shadowmap}}", vfs_read("shaders/fs_0_0_shadowmap_lit.glsl") };
-    s->program = shader(strlerp(1, symbols, vfs_read("shaders/vs_332_32.glsl")), strlerp(1, symbols, vfs_read("shaders/fs_32_4_model.glsl")), "att_position,att_normal,att_texcoord,att_color", "fragcolor", NULL);
     s->skybox = skybox(NULL, 0);
     array_push(scenes, s);
     last_scene = s;
@@ -416,7 +442,6 @@ void scene_render(int flags) {
     glEnable(GL_DEPTH_TEST);
     glDepthFunc(GL_LESS);
     glActiveTexture(GL_TEXTURE0);
-    glUseProgram(last_scene->program);
 
     if(flags & SCENE_BACKGROUND) {
         if(last_scene->skybox.program) {
@@ -437,7 +462,6 @@ void scene_render(int flags) {
 
     glDepthFunc(GL_LESS);
     glActiveTexture(GL_TEXTURE0);
-//  glUseProgram(last_scene->program);
 
     // @fixme: CW ok for one-sided rendering. CCW ok for FXs. we need both
     (flags & SCENE_CULLFACE ? glEnable : glDisable)(GL_CULL_FACE); glCullFace(GL_BACK); glFrontFace(GL_CCW);
diff --git a/engine/split/v4k_scene.h b/engine/split/v4k_scene.h
index b3962b1..480fe39 100644
--- a/engine/split/v4k_scene.h
+++ b/engine/split/v4k_scene.h
@@ -66,21 +66,28 @@ enum LIGHT_FLAGS {
 
 typedef struct light_t {
     char type;
-    vec3 color;
+    vec3 diffuse, specular, ambient;
     vec3 pos, dir;
-    float radius;
+    struct {
+        float constant, linear, quadratic;
+    } falloff;
+    float innerCone, outerCone;
+    //@todo: cookie, flare
+
+    // internals
     bool cached; //< used by scene to invalidate cached light data
-    //@todo: inner/outer cone, flags, cookie, flare
 } light_t;
 
 API light_t light();
 // API void    light_flags(int flags);
 API void    light_type(light_t* l, char type);
-API void    light_color(light_t* l, vec3 color);
+API void    light_diffuse(light_t* l, vec3 color);
+API void    light_specular(light_t* l, vec3 color);
+API void    light_ambient(light_t* l, vec3 color);
 API void    light_teleport(light_t* l, vec3 pos);
 API void    light_dir(light_t* l, vec3 dir);
-API void    light_radius(light_t* l, float radius);
-// API void    light_cone(light_t* l, float inner, float outer);
+API void    light_falloff(light_t* l, float constant, float linear, float quadratic);
+API void    light_cone(light_t* l, float innerCone, float outerCone);
 API void    light_update(unsigned num_lights, light_t *lv);
 
 // scene
@@ -94,8 +101,6 @@ enum SCENE_FLAGS {
 };
 
 typedef struct scene_t {
-    handle program;
-
     array(object_t) objs;
     array(light_t) lights;
 
diff --git a/engine/v4k.c b/engine/v4k.c
index e7b8006..e314d03 100644
--- a/engine/v4k.c
+++ b/engine/v4k.c
@@ -13947,6 +13947,24 @@ void model_set_uniforms(model_t m, int shader, mat44 mv, mat44 proj, mat44 view,
         mat44 vp; multiply44x2(vp, proj, view);
         glUniformMatrix4fv( loc, 1, GL_FALSE, vp);
     }
+    if( (loc = glGetUniformLocation(shader, "u_cam_pos")) >= 0 ) {
+        vec3 pos = vec3(view[3], view[6], view[9]);
+        glUniform3fv( loc, 1, &pos.x );
+    }
+    else
+    if( (loc = glGetUniformLocation(shader, "cam_pos")) >= 0 ) {
+        vec3 pos = vec3(view[3], view[6], view[9]);
+        glUniform3fv( loc, 1, &pos.x );
+    }
+    if( (loc = glGetUniformLocation(shader, "u_cam_dir")) >= 0 ) {
+        vec3 dir = vec3(view[0], view[1], view[2]);
+        glUniform3fv( loc, 1, &dir.x );
+    }
+    else
+    if( (loc = glGetUniformLocation(shader, "cam_dir")) >= 0 ) {
+        vec3 dir = vec3(view[0], view[1], view[2]);
+        glUniform3fv( loc, 1, &dir.x );
+    }
 #if 0
     // @todo: mat44 projview (useful?)
 #endif
@@ -14383,13 +14401,14 @@ model_t model_from_mem(const void *mem, int len, int flags) {
     model_t m = {0};
 
     const char *ptr = (const char *)mem;
-    static int shaderprog = -1;
-    if( shaderprog < 0 ) {
+    // can't cache shader programs since we enable features via flags here
+    // static int shaderprog = -1;
+    // if( shaderprog < 0 ) {
         const char *symbols[] = { "{{include-shadowmap}}", vfs_read("shaders/fs_0_0_shadowmap_lit.glsl") }; // #define RIM
-        shaderprog = shader(strlerp(1,symbols,vfs_read("shaders/vs_323444143_16_332_model.glsl")), strlerp(1,symbols,vfs_read("shaders/fs_32_4_model.glsl")), //fs,
+        int shaderprog = shader(strlerp(1,symbols,vfs_read("shaders/vs_323444143_16_332_model.glsl")), strlerp(1,symbols,vfs_read("shaders/fs_32_4_model.glsl")), //fs,
             "att_position,att_texcoord,att_normal,att_tangent,att_instanced_matrix,,,,att_indexes,att_weights,att_vertexindex,att_color,att_bitangent","fragColor",
-            (flags&MODEL_RIMLIGHT)?"RIM":NULL);
-    }
+            va("SHADING_PHONG,%s", (flags&MODEL_RIMLIGHT)?"RIM":""));
+    // }
 
     iqm_t *q = CALLOC(1, sizeof(iqm_t));
     program = shaderprog;
@@ -15852,9 +15871,13 @@ void object_billboard(object_t *obj, unsigned mode) {
 
 light_t light() {
     light_t l = {0};
-    l.color = vec3(1,1,1);
-    l.radius = 2.5f;
+    l.diffuse = vec3(1,1,1);
     l.dir = vec3(1,-1,-1);
+    l.falloff.constant = 1.0f;
+    l.falloff.linear = 0.09f;
+    l.falloff.quadratic = 0.0032f;
+    l.innerCone = 0.9f; // 25 deg
+    l.outerCone = 0.85f; // 31 deg
 
     return l;
 }
@@ -15864,9 +15887,19 @@ void light_type(light_t* l, char type) {
     l->type = type;
 }
 
-void light_color(light_t* l, vec3 color) {
+void light_diffuse(light_t* l, vec3 color) {
     l->cached = 0;
-    l->color = color;
+    l->diffuse = color;
+}
+
+void light_specular(light_t* l, vec3 color) {
+    l->cached = 0;
+    l->specular = color;
+}
+
+void light_ambient(light_t* l, vec3 color) {
+    l->cached = 0;
+    l->ambient = color;
 }
 
 void light_teleport(light_t* l, vec3 pos) {
@@ -15879,9 +15912,16 @@ void light_dir(light_t* l, vec3 dir) {
     l->dir = dir;
 }
 
-void light_radius(light_t* l, float radius) {
+void light_falloff(light_t* l, float constant, float linear, float quadratic) {
     l->cached = 0;
-    l->radius = radius;
+    l->falloff.constant = constant;
+    l->falloff.linear = linear;
+    l->falloff.quadratic = quadratic;
+}
+
+void light_cone(light_t* l, float innerCone, float outerCone) {
+    l->innerCone = acos(innerCone);
+    l->outerCone = acos(outerCone);
 }
 
 void light_update(unsigned num_lights, light_t *lv) {
@@ -15890,9 +15930,16 @@ void light_update(unsigned num_lights, light_t *lv) {
     for (unsigned i=0; i < num_lights; ++i) {
         lv[i].cached = 1;
         shader_int(va("u_lights[%d].type", i), lv[i].type);
-        shader_vec3(va("u_lights[%d].color", i), lv[i].color);
         shader_vec3(va("u_lights[%d].pos", i), lv[i].pos);
         shader_vec3(va("u_lights[%d].dir", i), lv[i].dir);
+        shader_vec3(va("u_lights[%d].diffuse", i), lv[i].diffuse);
+        shader_vec3(va("u_lights[%d].specular", i), lv[i].specular);
+        shader_vec3(va("u_lights[%d].ambient", i), lv[i].ambient);
+        shader_float(va("u_lights[%d].constant", i), lv[i].falloff.constant);
+        shader_float(va("u_lights[%d].linear", i), lv[i].falloff.linear);
+        shader_float(va("u_lights[%d].quadratic", i), lv[i].falloff.quadratic);
+        shader_float(va("u_lights[%d].innerCone", i), lv[i].innerCone);
+        shader_float(va("u_lights[%d].outerCone", i), lv[i].outerCone);
     }
 }
 
@@ -15913,8 +15960,6 @@ scene_t* scene_get_active() {
 
 scene_t* scene_push() {
     scene_t *s = REALLOC(0, sizeof(scene_t)), clear = {0}; *s = clear;
-    const char *symbols[] = { "{{include-shadowmap}}", vfs_read("shaders/fs_0_0_shadowmap_lit.glsl") };
-    s->program = shader(strlerp(1, symbols, vfs_read("shaders/vs_332_32.glsl")), strlerp(1, symbols, vfs_read("shaders/fs_32_4_model.glsl")), "att_position,att_normal,att_texcoord,att_color", "fragcolor", NULL);
     s->skybox = skybox(NULL, 0);
     array_push(scenes, s);
     last_scene = s;
@@ -16025,7 +16070,6 @@ void scene_render(int flags) {
     glEnable(GL_DEPTH_TEST);
     glDepthFunc(GL_LESS);
     glActiveTexture(GL_TEXTURE0);
-    glUseProgram(last_scene->program);
 
     if(flags & SCENE_BACKGROUND) {
         if(last_scene->skybox.program) {
@@ -16046,7 +16090,6 @@ void scene_render(int flags) {
 
     glDepthFunc(GL_LESS);
     glActiveTexture(GL_TEXTURE0);
-//  glUseProgram(last_scene->program);
 
     // @fixme: CW ok for one-sided rendering. CCW ok for FXs. we need both
     (flags & SCENE_CULLFACE ? glEnable : glDisable)(GL_CULL_FACE); glCullFace(GL_BACK); glFrontFace(GL_CCW);
diff --git a/engine/v4k.h b/engine/v4k.h
index 42ed38d..64cb9fa 100644
--- a/engine/v4k.h
+++ b/engine/v4k.h
@@ -3005,6 +3005,14 @@ enum MODEL_FLAGS {
     MODEL_RIMLIGHT = 16
 };
 
+//@todo: make this data-driven
+// enum SHADING_MODE {
+//     SHADING_NONE,
+//     SHADING_PHONG,
+//     SHADING_CARTOON,
+//     // SHADING_PBR,
+// };
+
 typedef struct model_t {
     struct iqm_t *iqm; // private
 
@@ -3247,21 +3255,28 @@ enum LIGHT_FLAGS {
 
 typedef struct light_t {
     char type;
-    vec3 color;
+    vec3 diffuse, specular, ambient;
     vec3 pos, dir;
-    float radius;
+    struct {
+        float constant, linear, quadratic;
+    } falloff;
+    float innerCone, outerCone;
+    //@todo: cookie, flare
+
+    // internals
     bool cached; //< used by scene to invalidate cached light data
-    //@todo: inner/outer cone, flags, cookie, flare
 } light_t;
 
 API light_t light();
 // API void    light_flags(int flags);
 API void    light_type(light_t* l, char type);
-API void    light_color(light_t* l, vec3 color);
+API void    light_diffuse(light_t* l, vec3 color);
+API void    light_specular(light_t* l, vec3 color);
+API void    light_ambient(light_t* l, vec3 color);
 API void    light_teleport(light_t* l, vec3 pos);
 API void    light_dir(light_t* l, vec3 dir);
-API void    light_radius(light_t* l, float radius);
-// API void    light_cone(light_t* l, float inner, float outer);
+API void    light_falloff(light_t* l, float constant, float linear, float quadratic);
+API void    light_cone(light_t* l, float innerCone, float outerCone);
 API void    light_update(unsigned num_lights, light_t *lv);
 
 // scene
@@ -3275,8 +3290,6 @@ enum SCENE_FLAGS {
 };
 
 typedef struct scene_t {
-    handle program;
-
     array(object_t) objs;
     array(light_t) lights;