gl_state_tracker: Implement dirty flags for alpha testing

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -1267,13 +1267,23 @@ void RasterizerOpenGL::SyncPolygonOffset() {
 }
 
 void RasterizerOpenGL::SyncAlphaTest() {
-    const auto& regs = system.GPU().Maxwell3D().regs;
-    UNIMPLEMENTED_IF_MSG(regs.alpha_test_enabled != 0 && regs.rt_control.count > 1,
-                         "Alpha Testing is enabled with more than one rendertarget");
+    auto& gpu = system.GPU().Maxwell3D();
+    auto& flags = gpu.dirty.flags;
+    if (!flags[Dirty::AlphaTest]) {
+        return;
+    }
+    flags[Dirty::AlphaTest] = false;
+
+    const auto& regs = gpu.regs;
+    if (regs.alpha_test_enabled && regs.rt_control.count > 1) {
+        LOG_WARNING(Render_OpenGL, "Alpha testing with more than one render target is not tested");
+    }
 
-    oglEnable(GL_ALPHA_TEST, regs.alpha_test_enabled);
     if (regs.alpha_test_enabled) {
+        glEnable(GL_ALPHA_TEST);
         glAlphaFunc(MaxwellToGL::ComparisonOp(regs.alpha_test_func), regs.alpha_test_ref);
+    } else {
+        glDisable(GL_ALPHA_TEST);
     }
 }
 

src/video_core/renderer_opengl/gl_state_tracker.cpp

@@ -149,6 +149,13 @@ void SetupDirtyStencilTest(Tables& tables) {
     }
 }
 
+void SetupDirtyAlphaTest(Tables& tables) {
+    auto& table = tables[0];
+    table[OFF(alpha_test_ref)] = AlphaTest;
+    table[OFF(alpha_test_func)] = AlphaTest;
+    table[OFF(alpha_test_enabled)] = AlphaTest;
+}
+
 void SetupDirtyBlend(Tables& tables) {
     FillBlock(tables[0], OFF(blend_color), NUM(blend_color), BlendColor);
 
@@ -205,6 +212,7 @@ void StateTracker::Initialize() {
     SetupDirtyShaders(tables);
     SetupDirtyDepthTest(tables);
     SetupDirtyStencilTest(tables);
+    SetupDirtyAlphaTest(tables);
     SetupDirtyBlend(tables);
     SetupDirtyPrimitiveRestart(tables);
     SetupDirtyPolygonOffset(tables);

src/video_core/renderer_opengl/gl_state_tracker.h

@@ -62,6 +62,7 @@ enum : u8 {
     DepthMask,
     DepthTest,
     StencilTest,
+    AlphaTest,
     PrimitiveRestart,
     PolygonOffset,
 

src/video_core/renderer_opengl/renderer_opengl.cpp

@@ -195,7 +195,7 @@ layout (location = 0) out vec4 color;
 layout (binding = 0) uniform sampler2D color_texture;
 
 void main() {
-    color = texture(color_texture, frag_tex_coord);
+    color = vec4(texture(color_texture, frag_tex_coord).rgb, 1.0f);
 }
 )";
 
@@ -600,7 +600,6 @@ void RendererOpenGL::DrawScreen(const Layout::FramebufferLayout& layout) {
         glDisable(GL_FRAMEBUFFER_SRGB);
     }
     glDisable(GL_COLOR_LOGIC_OP);
-    glDisable(GL_ALPHA_TEST);
     glDisable(GL_DEPTH_TEST);
     glDisable(GL_STENCIL_TEST);
     glDisable(GL_POLYGON_OFFSET_FILL);