Fix syntax on Linux; drop GL version to 3.3

examples/generate-atlas.rs

@@ -32,7 +32,7 @@ const SHELF_HEIGHT: u32 = 32;
 
 fn main() {
     let mut glfw = glfw::init(glfw::LOG_ERRORS).unwrap();
-    glfw.window_hint(WindowHint::ContextVersion(4, 1));
+    glfw.window_hint(WindowHint::ContextVersion(3, 3));
     glfw.window_hint(WindowHint::OpenGlForwardCompat(true));
     glfw.window_hint(WindowHint::OpenGlProfile(OpenGlProfileHint::Core));
     let context = glfw.create_window(WIDTH, HEIGHT, "generate-atlas", WindowMode::Windowed);

resources/shaders/accum.cs.glsl

@@ -17,9 +17,12 @@
 #version 330
 #extension GL_ARB_compute_shader : require
 #extension GL_ARB_explicit_uniform_location : require
+#extension GL_ARB_shader_image_load_store : require
 #extension GL_ARB_shader_storage_buffer_object : require
 
-uniform uimage2DRect uTexture;
+layout(local_size_x = 1024) in;
+
+uniform restrict writeonly uimage2DRect uTexture;
 uniform sampler2DRect uCoverage;
 uniform uvec4 uAtlasRect;
 uniform uint uAtlasShelfHeight;
@@ -29,13 +32,14 @@ void main() {
     uint atlasWidth = uAtlasRect.z - uAtlasRect.x;
     uint column = gl_GlobalInvocationID.x % atlasWidth;
     uint shelfIndex = gl_GlobalInvocationID.x / atlasWidth;
-    uint firstRow = shelfIndex * uAtlasShelfHeight, lastRow = (shelfIndex + 1) * uAtlasShelfHeight;
+    uint firstRow = shelfIndex * uAtlasShelfHeight;
+    uint lastRow = (shelfIndex + 1u) * uAtlasShelfHeight;
 
     // Sweep down the column, accumulating coverage as we go.
     float coverage = 0.0f;
     for (uint row = firstRow; row < lastRow; row++) {
         ivec2 coord = ivec2(column, row);
-        coverage += texelFetch(uCoverage, coord);
+        coverage += texelFetch(uCoverage, coord).r;
 
         uint gray = uint(clamp(coverage, 0.0f, 1.0f) * 255.0f);
         imageStore(uTexture, coord + ivec2(uAtlasRect.xy), uvec4(gray, 255, 255, 255));

resources/shaders/draw.fs.glsl

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#version 410
+#version 330
 
 // The size of the atlas in pixels.
 uniform uvec2 uAtlasSize;

resources/shaders/draw.gs.glsl

@@ -17,7 +17,7 @@
 // To use this shader, set `RasterizerOptions::force_geometry_shader` to true or set the
 // environment variable `PATHFINDER_FORCE_GEOMETRY_SHADER` to 1.
 
-#version 410
+#version 330
 
 #define CURVE_THRESHOLD         0.333f
 #define CURVE_TOLERANCE         3.0f
@@ -39,7 +39,7 @@ layout(triangle_strip, max_vertices = 256) out;
 uniform uvec2 uAtlasSize;
 
 // The vertex ID, passed into this shader.
-flat in uint vVertexID[];
+flat in int vVertexID[];
 
 // The starting point of the segment.
 flat out vec2 vP0;
@@ -69,7 +69,7 @@ void main() {
     }
 
     // Determine how many lines to divide into.
-    uint lineCount = 1;
+    uint lineCount = 1u;
     if (vVertexID[1] > 0) {
         // Quadratic curve.
         vec2 dev = p0 - 2.0f * p1 + p2;
@@ -82,16 +82,16 @@ void main() {
     }
 
     // Divide into lines.
-    for (uint lineIndex = 0; lineIndex < lineCount; lineIndex++) {
+    for (uint lineIndex = 0u; lineIndex < lineCount; lineIndex++) {
         // Compute our endpoints (trivial if this is part of a line, less trivial if this is part
         // of a curve).
         vec2 lP0, lP1;
-        if (lineCount == 1) {
+        if (lineCount == 1u) {
             lP0 = p0;
             lP1 = p2;
         } else {
-            float t0 = float(lineIndex + 0) / float(lineCount);
+            float t0 = float(lineIndex + 0u) / float(lineCount);
-            float t1 = float(lineIndex + 1) / float(lineCount);
+            float t1 = float(lineIndex + 1u) / float(lineCount);
             lP0 = mix(mix(p0, p1, t0), mix(p1, p2, t0), t0);
             lP1 = mix(mix(p0, p1, t1), mix(p1, p2, t1), t1);
         }

resources/shaders/draw.tcs.glsl

@@ -16,7 +16,7 @@
 layout(vertices = 1) out;
 
 // The vertex ID, passed into this shader.
-flat in uint vVertexID[];
+flat in int vVertexID[];
 
 // The starting point of the segment.
 patch out vec2 vpP0;

resources/shaders/draw.vs.glsl

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#version 410
+#version 330
 
 #define MAX_GLYPHS  2048
 
@@ -45,7 +45,7 @@ in ivec2 aPosition;
 in uint aGlyphIndex;
 
 // The vertex ID, passed along onto the TCS.
-flat out uint vVertexID;
+flat out int vVertexID;
 
 void main() {
     vVertexID = gl_VertexID;