v4k-git-backup/engine/art/shaders/vs_font.glsl

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2024-02-12 09:56:46 +00:00
in vec2 vertexPosition;
in vec4 instanceGlyph;
uniform sampler2D sampler_font;
uniform sampler2D sampler_meta;
uniform float offset_firstline; // ascent
uniform float scale_factor; // scaling factor proportional to font size
uniform vec2 string_offset; // offset of upper-left corner
uniform vec2 res_meta; // 96x2
uniform vec2 res_bitmap; // 512x256
uniform vec2 resolution; // screen resolution
out vec2 uv;
out float color_index; // for syntax highlighting
void main() {
// (xoff, yoff, xoff2, yoff2), from second row of texture
vec4 q2 = texture(sampler_meta, vec2((instanceGlyph.z + 0.5)/res_meta.x, 0.75))*vec4(res_bitmap, res_bitmap);
vec2 p = vertexPosition*(q2.zw - q2.xy) + q2.xy; // offset and scale it properly relative to baseline
p *= vec2(1.0, -1.0); // flip y, since texture is upside-down
p.y -= offset_firstline; // make sure the upper-left corner of the string is in the upper-left corner of the screen
p *= scale_factor; // scale relative to font size
p += instanceGlyph.xy + string_offset; // move glyph into the right position
p *= 2.0/resolution; // to NDC
p += vec2(-1.0, 1.0); // move to upper-left corner instead of center
gl_Position = vec4(p, 0.0, 1.0);
// (x0, y0, x1-x0, y1-y0), from first row of texture
vec4 q = texture(sampler_meta, vec2((instanceGlyph.z + 0.5)/res_meta.x, 0.25));
// send the correct uv's in the font atlas to the fragment shader
uv = q.xy + vertexPosition*q.zw;
color_index = instanceGlyph.w;
}