Use alpha to coverage and alpha test for text;

src/graphics/graphics.c

@@ -889,15 +889,14 @@ void lovrGraphicsPrint(const char* str, mat4 transform, float wrap, HorizontalAl
   lovrGraphicsMatrixTransform(transform);
   lovrGraphicsScale(scale, scale, scale);
   lovrGraphicsTranslate(0, offsety, 0);
-  lovrGraphicsPushPipeline();
-  state.pipelines[state.pipeline].depthWrite = false;
+  state.pipelines[state.pipeline].alphaCoverage = true;
   lovrGraphicsDraw(&(DrawCommand) {
     .shader = SHADER_FONT,
     .textures[TEXTURE_DIFFUSE] = font->texture,
     .mode = MESH_TRIANGLES,
     .range = { 0, vertexCount }
   });
-  lovrGraphicsPopPipeline();
+  state.pipelines[state.pipeline].alphaCoverage = false;
   lovrGraphicsPop();
 }
 

src/graphics/graphics.h

@@ -93,6 +93,7 @@ typedef struct {
 } Camera;
 
 typedef struct {
+  bool alphaCoverage;
   Color backgroundColor;
   BlendMode blendMode;
   BlendAlphaMode blendAlphaMode;

src/graphics/opengl.c

@@ -47,6 +47,7 @@ typedef enum {
 
 static struct {
   Texture* defaultTexture;
+  bool alphaCoverage;
   BlendMode blendMode;
   BlendAlphaMode blendAlphaMode;
   bool culling;
@@ -629,6 +630,9 @@ void lovrGpuInit(bool srgb, getGpuProcProc getProcAddress) {
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
   state.srgb = srgb;
 
+  state.alphaCoverage = false;
+  glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+
   state.blendMode = BLEND_ALPHA;
   state.blendAlphaMode = BLEND_ALPHA_MULTIPLY;
   glBlendEquation(GL_FUNC_ADD);
@@ -682,6 +686,16 @@ void lovrGpuDestroy() {
 
 void lovrGpuBindPipeline(Pipeline* pipeline) {
 
+  // Alpha Coverage
+  if (state.alphaCoverage != pipeline->alphaCoverage) {
+    state.alphaCoverage = pipeline->alphaCoverage;
+    if (state.alphaCoverage) {
+      glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+    } else {
+      glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+    }
+  }
+
   // Blend mode
   if (state.blendMode != pipeline->blendMode || state.blendAlphaMode != pipeline->blendAlphaMode) {
     state.blendMode = pipeline->blendMode;

src/resources/shaders.c

@@ -137,6 +137,7 @@ const char* lovrFontFragmentShader = ""
 "  float sdf = median(col.r, col.g, col.b); \n"
 "  float w = fwidth(sdf); \n"
 "  float alpha = smoothstep(.5 - w, .5 + w, sdf); \n"
+"  if (alpha <= 0.0) discard; \n"
 "  return vec4(graphicsColor.rgb, graphicsColor.a * alpha); \n"
 "}";