ecere/gfx/drivers/GL/GLAB: Improved handling element buffers with VAO

- Not modifying active element buffer when VAOs are on, except for default VAO
- Not using glabCurElementBuffer with VAO except for defaultVAO, as each VAO may have a different active element buffer
- Removed unecessary / wrong WebGL-specific logic
- New GLABBindVertexArray() call to keep track of active VAO
- NOTE: VAO usage currently expects a single context / display
- butterbur: Updated to use GLABBindVertexArray()
- samples/3D/CubicWorld: Updated to use GLABBindVertexArray()
- samples/3D/CubicWorld: Improved readability e.g., splitting prepareMultiDraw() into multiple methods

butterbur/src/opengl/shaders/butterbur.frag

@@ -428,7 +428,8 @@ void main(void)
 
 #if FOG_ON
    {
-      float fog = clamp(exp(fogZ), 0.0, 1.0);
+      float fog = clamp(exp(-fogZ * fogZ), 0.0, 1.0);
+      //float fog = clamp(exp(fogZ), 0.0, 1.0);
       c = vec4(fog * c.xyz + (1.0 - fog) * fogColor, c.w);
    }
 #endif

butterbur/src/presentation/DrawingManager.ec

@@ -134,7 +134,7 @@ public class MDManager : DrawingManager
          }
       }
 
-      if(glCaps_vao) glBindVertexArray(0);
+      if(glCaps_vao) GLABBindVertexArray(0);
    }
 }
 
@@ -227,7 +227,7 @@ class Perspective3DManager : MDManager
       GLFlushMatrices();
 
       texture.bind();
-      if(glCaps_vao) glBindVertexArray(md.vao);
+      if(glCaps_vao) GLABBindVertexArray(md.vao);
       for(n = 0; n < md.commandsCount; n++)
       {
          const GLDrawCommand *cmd = &md.commands[n];
@@ -251,7 +251,7 @@ class Perspective3DManager : MDManager
          glDisableVertexAttribArray(transform2Attribute);
          glDisableVertexAttribArray(transform3Attribute);
       }*/
-      if(glCaps_vao) glBindVertexArray(0);
+      if(glCaps_vao) GLABBindVertexArray(0);
 
       butterburShader.transform3D = false;
    }
@@ -264,7 +264,7 @@ class Perspective3DManager : MDManager
          {
             PrimitiveGroup group;
 
-            if(glCaps_vao) glBindVertexArray(defaultVAO);
+            if(glCaps_vao) GLABBindVertexArray(defaultVAO);
             glDisplay.SelectMesh(mesh);
 
             for(group = mesh.groups.first; group; group = group.next)
@@ -283,7 +283,7 @@ class Perspective3DManager : MDManager
                glDisplay.DrawPrimitives((PrimitiveSingle *)&group.type, mesh);
             }
 
-            if(glCaps_vao) glBindVertexArray(0);
+            if(glCaps_vao) GLABBindVertexArray(0);
          }
       }
    }

butterbur/src/presentation/GraphicalSurface.ec

@@ -113,7 +113,7 @@ public class GraphicalSurface : MultiPresentation
 #endif
 
       glDisable(GL_SCISSOR_TEST);
-      if(glCaps_vao) glBindVertexArray(0);
+      if(glCaps_vao) GLABBindVertexArray(0);
       glBindFramebuffer(GL_FRAMEBUFFER, texturesFramebuffer);
       butterburShader.activate();
       butterburShader.lighting(false);
@@ -268,7 +268,7 @@ public class GraphicalSurface : MultiPresentation
       butterburShader.textureArray(false);
       glBindTexture(GL_TEXTURE_2D_ARRAY, 0);
       glEnable(GL_SCISSOR_TEST);
-      if(glCaps_vao) glBindVertexArray(defaultVAO);
+      if(glCaps_vao) GLABBindVertexArray(defaultVAO);
       DefaultShader::shader().texturing(false);
       DefaultShader::shader().texturing(true);
       DefaultShader::shader().activate();

butterbur/src/presentation/TIManager.ec

@@ -69,19 +69,19 @@ public class TIManager : DrawingManager
       float transform[2] = { originOffset.x, originOffset.y };
       if(drawManager)
          drawManager.ready(width, height);
-      if(glCaps_vao) glBindVertexArray(defaultVAO);
+      if(glCaps_vao) GLABBindVertexArray(defaultVAO);
       presentation.prepareDraw(renderFlags, this, transform);
    }
 
    void draw()
    {
       // TODO: Proper VAO support for text & images?
-      if(glCaps_vao) glBindVertexArray(defaultVAO);
+      if(glCaps_vao) GLABBindVertexArray(defaultVAO);
       if(drawManager)
          drawManager.flushImages();
       if(glCaps_shaders)
          glEnableVertexAttribArray(GLBufferContents::vertex);
-      if(glCaps_vao) glBindVertexArray(0);
+      if(glCaps_vao) GLABBindVertexArray(0);
    }
 
    void addTextCommand(const String text, GEFont font, float opacity, Alignment2D alignment, float * transform)

ecere/src/gfx/drivers/OpenGLDisplayDriver.ec

@@ -398,6 +398,8 @@ Shader activeShader;
 
 static int displayWidth, displayHeight;
 
+uint defaultVAO; // Only works with a single display / context
+
 static bool useSingleGLContext = false;
 class OGLDisplay : struct
 {
@@ -1373,8 +1375,11 @@ class OpenGLDisplayDriver : DisplayDriver
 #if ENABLE_GL_VAO
       if(oglDisplay.capabilities.vao)
       {
+         // VAOs cannot be shared across contexts, but in single context mode
+         // we should re-use the same VAO across displays.
          glGenVertexArrays(1, &oglDisplay.vao);
-         glBindVertexArray(oglDisplay.vao);
+         defaultVAO = oglDisplay.vao; // NOTE: This currently only works with a single display / context
+         GLABBindVertexArray(oglDisplay.vao);
       }
 #endif
 
@@ -1413,8 +1418,7 @@ class OpenGLDisplayDriver : DisplayDriver
          GLDisableClientState(TANGENTS1);
          GLDisableClientState(TANGENTS2);
 #if ENABLE_GL_VAO
-         if(glBindVertexArray)
-            glBindVertexArray(0);
+         GLABBindVertexArray(0);
 #endif
          if(glUseProgram)
             glUseProgram(0);
@@ -1425,7 +1429,7 @@ class OpenGLDisplayDriver : DisplayDriver
 
 #if ENABLE_GL_VAO
       if(glCaps_vao)
-         glBindVertexArray(oglDisplay.vao);
+         GLABBindVertexArray(oglDisplay.vao);
 #endif
 
       GLEnableClientState(VERTICES);
@@ -2039,7 +2043,7 @@ class OpenGLDisplayDriver : DisplayDriver
       if(glCaps_vao)
       {
          OGLDisplay oglDisplay = display.driverData;
-         glBindVertexArray(oglDisplay.vao);
+         GLABBindVertexArray(oglDisplay.vao);
       }
 #endif
       GLABBindBuffer(GL_ARRAY_BUFFER, 0);

ecere/src/gfx/drivers/gl3/GLMultiDraw.ec

@@ -639,7 +639,7 @@ public struct GLMultiDraw
 
       // TOCHECK: No attrib divisor support in ES 2 -- will it be needed?
 #if (!defined(_GLES) && !defined(_GLES2)) || defined(_GLES3)
-      if(glCaps_vao) glBindVertexArray(vao);
+      if(glCaps_vao) GLABBindVertexArray(vao);
 
 #ifndef CLIENT_MEM_COMMANDS
       commandsB.upload(0, commandsCount * sizeof(GLDrawCommand), commands);
@@ -681,7 +681,7 @@ public struct GLMultiDraw
       // TOCHECK: Should this re-do all the use() here if there is no VAO support?
 
 #if (!defined(_GLES) && !defined(_GLES2)) || defined(_GLES3)
-      if(glCaps_vao) glBindVertexArray(vao);
+      if(glCaps_vao) GLABBindVertexArray(vao);
 #endif
       GLFlushMatrices();
 
@@ -696,10 +696,18 @@ public struct GLMultiDraw
          GLAB ab { vertexGLMB.ab.buffer };
          Shader shader = activeShader;
 
-         GLABBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexGLMB.ab.buffer);
+         if(!glCaps_vao)   // Don't modify VAO state.
+         {
+            GLABBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexGLMB.ab.buffer);
+
+            glDisableVertexAttribArray((GLBufferContents)drawIDAttribute);
+            glDisableVertexAttribArray((GLBufferContents)posOffsetAttribute);
+         }
+         else if(vao == defaultVAO)
+            PrintLn("WARNING: MultiDraw with default VAO");
+         else if(!glabCurVertexArray)
+            PrintLn("WARNING (MultiDraw): No VAO selected");
 
-         glDisableVertexAttribArray((GLBufferContents)drawIDAttribute);
-         glDisableVertexAttribArray((GLBufferContents)posOffsetAttribute);
          for(n = 0; n < commandsCount; n++)
          {
             const GLDrawCommand *cmd = &commands[n];
@@ -783,7 +791,7 @@ public struct GLMultiDraw
 #endif
 #endif
 #if (!defined(_GLES) && !defined(_GLES2)) || defined(_GLES3)
-      if(glCaps_vao) glBindVertexArray(0);
+      if(glCaps_vao) GLABBindVertexArray(0);
 #endif
    }
 };

ecere/src/gfx/drivers/gl3/glab.ec

@@ -15,7 +15,7 @@ default dllexport void GLABUnbindBuffer(int target)
       glBindBuffer(target, 0);
       if(target == GL_ARRAY_BUFFER)
          glabCurArrayBuffer = 0;
-      else if(target == GL_ELEMENT_ARRAY_BUFFER)
+      else if(target == GL_ELEMENT_ARRAY_BUFFER && (!glCaps_vao || glabCurVertexArray == defaultVAO))
          glabCurElementBuffer = 0;
 // NOTE: Actually ES 3.1 is required, separate define?
 #if !defined(_GLES) && !defined(_GLES2) && !defined(_GLES3)
@@ -33,7 +33,7 @@ public void GLABBindBuffer(int target, uint buffer)
       glBindBuffer(target, buffer);
       if(target == GL_ARRAY_BUFFER)
          glabCurArrayBuffer = buffer;
-      else if(target == GL_ELEMENT_ARRAY_BUFFER)
+      else if(target == GL_ELEMENT_ARRAY_BUFFER && (!glCaps_vao || glabCurVertexArray == defaultVAO))
          glabCurElementBuffer = buffer;
 // NOTE: Actually ES 3.1 is required, separate define?
 #if !defined(_GLES) && !defined(_GLES2) && !defined(_GLES3)
@@ -43,10 +43,6 @@ public void GLABBindBuffer(int target, uint buffer)
    }
 }
 
-#if !defined(_GLES) && !defined(_GLES2) && !defined(_GLES3)
-uint glabCurDrawIndirectBuffer;
-#endif
-
 public enum GLBufferContents { vertex, normal, texCoord, color, tangent1, tangent2, lightVector, boneIndices1, boneIndices2, boneIndices3, boneWeights1, boneWeights2, boneWeights3 };
 
 public enum GLBufferUsage { staticDraw, dynamicDraw, streamDraw };
@@ -55,7 +51,29 @@ static GLint bufferUsages[] = { GL_STATIC_DRAW, GL_DYNAMIC_DRAW, 0x88E0 /*GL_STR
 
 public define noAB = GLAB { 0 };
 
-uint glabCurArrayBuffer;
+public void GLABBindVertexArray(uint vao)
+{
+#if (!defined(_GLES) && !defined(_GLES2)) || defined(_GLES3)
+   if(glCaps_vao) // && vao != glabCurVertexArray) // VAOs are not shared across contexts / displays
+   {
+#ifdef _DEBUG
+      if(vao != glabCurVertexArray)
+         ;//PrintLn("WARNING: Redundant VAO binding");
+#endif
+      glBindVertexArray(vao);
+      glabCurVertexArray = vao;
+   }
+#endif
+}
+
+uint glabCurVertexArray;      // Currently bound VAO.
+
+uint glabCurArrayBuffer;      // Buffer currently bound for GL_ARRAY_BUFFER. *NOT* part of VAO state
+uint glabCurElementBuffer;    // Buffer currently bound for GL_ELEMENT_ARRAY_BUFFER. This *IS* part of the VAO state. With VAOs, this is for 'defaultVAO'.
+
+#if !defined(_GLES) && !defined(_GLES2) && !defined(_GLES3)
+uint glabCurDrawIndirectBuffer;
+#endif
 
 static short *shortVPBuffer = null;
 static uint shortVPSize = 0;
@@ -508,7 +526,7 @@ public struct GLB
             {
                if(buffer == glabCurArrayBuffer)
                   GLABBindBuffer(GL_ARRAY_BUFFER, 0);
-               else if(buffer == glabCurElementBuffer)
+               else if(buffer == glabCurElementBuffer && (!glCaps_vao || glabCurVertexArray == defaultVAO))
                   GLABBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 #if !defined(_GLES) && !defined(_GLES2) && !defined(_GLES3)
                else if(buffer == glabCurDrawIndirectBuffer)
@@ -620,8 +638,6 @@ public struct GLAB : GLB
    }
 };
 
-uint glabCurElementBuffer;
-
 public define noEAB = GLEAB { 0 };
 
 public struct GLCAB : GLB
@@ -657,11 +673,13 @@ public struct GLEAB : GLB
 #endif
          ))
       {
-
-#if !defined(__EMSCRIPTEN__)
-         if(glCaps_vertexBuffer && glabCurElementBuffer != ((this != null) ? buffer : 0))
-#endif
-            GLABBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ((this != null) ? buffer : 0));
+         if(!glCaps_vao || glabCurVertexArray == defaultVAO)
+         {
+            if(glCaps_vertexBuffer && glabCurElementBuffer != ((this != null) ? buffer : 0))
+               GLABBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ((this != null) ? buffer : 0));
+         }
+         else if(glCaps_vao && !glabCurVertexArray)
+            PrintLn("WARNING (draw): No VAO selected");
          if(!glCaps_intAndDouble)
             type = GL_UNSIGNED_SHORT;
 
@@ -680,11 +698,14 @@ public struct GLEAB : GLB
 #endif
          ))
       {
-#if !defined(__EMSCRIPTEN__)
-         if(glCaps_vertexBuffer)
-#endif
-         if(glabCurElementBuffer != ((this != null) ? buffer : 0))
-            GLABBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ((this != null) ? buffer : 0));
+         if(!glCaps_vao || glabCurVertexArray == defaultVAO)
+         {
+            if(glCaps_vertexBuffer && glabCurElementBuffer != ((this != null) ? buffer : 0))
+               GLABBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ((this != null) ? buffer : 0));
+         }
+         else if(glCaps_vao && !glabCurVertexArray)
+            PrintLn("WARNING (draw2): No VAO selected");
+
          if(!glCaps_intAndDouble)
             type = GL_UNSIGNED_SHORT;