Add working monospace text indexing to shader

1 files changed, 20 insertions, 5 deletions

diff --git a/src/main.c b/src/main.c
index 2a901a3..543ef86 100644
--- a/src/main.c
+++ b/src/main.c
@@ -216,9 +216,9 @@ render(Context *ctx) {
         f32 idx;
     };
     struct Letter letters[] = {
-        {-0.25, 0.0, 0},
-        {0.0,   0.0, 1},
-        {0.25,  0.0, 2},
+        {0, 0.0, 0},
+        {1, 0.0, 1},
+        {2, 0.0, 2},
     };
     u32 offset_vbo;
     glGenBuffers(1, &offset_vbo);
@@ -259,6 +259,7 @@ render(Context *ctx) {
     glBindBuffer(GL_ARRAY_BUFFER, 0);
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 
+    // TODO: Store the shaders as separate files for easier editing.
     const char* vert_src =
 "#version 330 core\n"
 "layout (location = 0) in vec2 position;\n"
@@ -266,11 +267,25 @@ render(Context *ctx) {
 "layout (location = 2) in vec3 offset;\n"
 "out vec2 tex;\n"
 "void main() {\n"
-"    float idx = offset.z;\n"
+// TODO: Uniforms
+"    float w = 800;\n"
+"    float h = 600;\n"
+"    float size = 5;\n"
 "    float N = 3;\n"
+
+"    float idx = offset.z;\n"
 "    float m = 1.0 / N;\n"
 "    float k = m * idx;\n"
-"    gl_Position = vec4(position / 8 + offset.xy, 0.0, 1.0);\n"
+// TODO: Only 8x8 monospace fonts for now
+"    float font_w = 8;\n"
+"    float font_h = 8;\n"
+// NOTE: This makes sures that the fonts have the right size.
+"    vec2 scalar = vec2(font_w / w, font_h / h) * size;\n"
+"    vec2 pos = tex_coords * scalar;\n"
+"    pos += vec2(0.0, 1.0 - scalar.y);\n"
+"    pos += scalar * offset.xy;\n"
+"    pos = mix(vec2(-1.0), vec2(1.0), pos);\n"
+"    gl_Position = vec4(pos, 0.0, 1.0);\n"
 "    tex = tex_coords * vec2(m, 1.0) + vec2(k, 0.0);\n"
 "}";