REVIEWED: DrawMeshInstanced()

examples/shaders/shaders_rlgl_mesh_instanced.c

@@ -59,15 +59,15 @@ int main(void)
     camera.fovy = 45.0f;
     camera.projection = CAMERA_PERSPECTIVE;
 
-    const int count = 10000;                                 // Number of instances to display 
+    const int instances = 10000;                                // Number of instances to display 
     Mesh cube = GenMeshCube(1.0f, 1.0f, 1.0f);
 
-    Matrix *rotations = RL_MALLOC(count*sizeof(Matrix));    // Rotation state of instances
-    Matrix *rotationsInc = RL_MALLOC(count*sizeof(Matrix)); // Per-frame rotation animation of instances
-    Matrix *translations = RL_MALLOC(count*sizeof(Matrix)); // Locations of instances
+    Matrix *rotations = RL_MALLOC(instances*sizeof(Matrix));    // Rotation state of instances
+    Matrix *rotationsInc = RL_MALLOC(instances*sizeof(Matrix)); // Per-frame rotation animation of instances
+    Matrix *translations = RL_MALLOC(instances*sizeof(Matrix)); // Locations of instances
 
     // Scatter random cubes around
-    for (int i = 0; i < count; i++)
+    for (int i = 0; i < instances; i++)
     {
         x = GetRandomValue(-50, 50);
         y = GetRandomValue(-50, 50);
@@ -84,7 +84,7 @@ int main(void)
         rotations[i] = MatrixIdentity();
     }
 
-    Matrix *transforms = RL_MALLOC(count*sizeof(Matrix));   // Pre-multiplied transformations passed to rlgl
+    Matrix *transforms = RL_MALLOC(instances*sizeof(Matrix));   // Pre-multiplied transformations passed to rlgl
 
     Shader shader = LoadShader(TextFormat("resources/shaders/glsl%i/base_lighting_instanced.vs", GLSL_VERSION), 
                                TextFormat("resources/shaders/glsl%i/lighting.fs", GLSL_VERSION));
@@ -107,19 +107,18 @@ int main(void)
     SetCameraMode(camera, CAMERA_ORBITAL);  // Set an orbital camera mode
 
     int textPositionY = 300;
-    
-    int framesCounter = 0;               // Simple frames counter to manage animation
+    int framesCounter = 0;                  // Simple frames counter to manage animation
 
-    SetTargetFPS(fps);                   // Set our game to run at 60 frames-per-second
+    SetTargetFPS(fps);                      // Set our game to run at 60 frames-per-second
     //--------------------------------------------------------------------------------------
 
     // Main game loop
-    while (!WindowShouldClose())        // Detect window close button or ESC key
+    while (!WindowShouldClose())            // Detect window close button or ESC key
     {
 
         // Update
         //----------------------------------------------------------------------------------
-        UpdateCamera(&camera);
+        textPositionY = 300;
         framesCounter++;
 
         if (IsKeyDown(KEY_UP)) amp += 0.5f;
@@ -148,7 +147,7 @@ int main(void)
         SetShaderValue(shader, shader.locs[SHADER_LOC_VECTOR_VIEW], cameraPos, SHADER_UNIFORM_VEC3);
 
         // Apply per-instance transformations
-        for (int i = 0; i < count; i++)
+        for (int i = 0; i < instances; i++)
         {
             rotations[i] = MatrixMultiply(rotations[i], rotationsInc[i]);
             transforms[i] = MatrixMultiply(rotations[i], translations[i]);
@@ -164,6 +163,8 @@ int main(void)
             
             transforms[i] = MatrixMultiply(transforms[i], MatrixTranslate(0.0f, y, 0.0f));
         }
+        
+        UpdateCamera(&camera);
         //----------------------------------------------------------------------------------
 
         // Draw
@@ -173,7 +174,7 @@ int main(void)
             ClearBackground(RAYWHITE);
 
             BeginMode3D(camera);
-                DrawMeshInstanced(cube, material, transforms, count);
+                DrawMeshInstanced(cube, material, transforms, instances);
             EndMode3D();
 
             DrawText("A CUBE OF DANCING CUBES!", 490, 10, 20, MAROON);

src/models.c

@@ -924,6 +924,12 @@ void UploadMesh(Mesh *mesh, bool dynamic)
 
 // Draw a 3d mesh with material and transform
 void DrawMesh(Mesh mesh, Material material, Matrix transform)
+{
+    DrawMeshInstanced(mesh, material, &transform, 1);
+}
+
+// Draw multiple mesh instances with material and different transforms
+void DrawMeshInstanced(Mesh mesh, Material material, Matrix *transforms, int instances)
 {
 #if defined(GRAPHICS_API_OPENGL_11)
     #define GL_VERTEX_ARRAY         0x8074
@@ -939,7 +945,7 @@ void DrawMesh(Mesh mesh, Material material, Matrix transform)
     rlEnableStatePointer(GL_COLOR_ARRAY, mesh.colors);
     
     rlPushMatrix();
-        rlMultMatrixf(MatrixToFloat(transform));
+        rlMultMatrixf(MatrixToFloat(transforms[0]));
         rlColor4ub(material.maps[MATERIAL_MAP_DIFFUSE].color.r, 
                    material.maps[MATERIAL_MAP_DIFFUSE].color.g, 
                    material.maps[MATERIAL_MAP_DIFFUSE].color.b, 
@@ -961,14 +967,8 @@ void DrawMesh(Mesh mesh, Material material, Matrix transform)
     // Bind shader program
     rlEnableShader(material.shader.id);
 
-    // Matrices and other values required by shader
+    // Send required data to shader (matrices, values)
     //-----------------------------------------------------
-    // Calculate and send to shader model matrix
-    if (material.shader.locs[SHADER_LOC_MATRIX_MODEL] != -1) 
-    {
-        rlSetUniformMatrix(material.shader.locs[SHADER_LOC_MATRIX_MODEL], transform);
-    }
-
     // Upload to shader material.colDiffuse
     if (material.shader.locs[SHADER_LOC_COLOR_DIFFUSE] != -1)
     {
@@ -998,16 +998,63 @@ void DrawMesh(Mesh mesh, Material material, Matrix transform)
     if (material.shader.locs[SHADER_LOC_MATRIX_VIEW] != -1) rlSetUniformMatrix(material.shader.locs[SHADER_LOC_MATRIX_VIEW], rlGetMatrixModelview());
     if (material.shader.locs[SHADER_LOC_MATRIX_PROJECTION] != -1) rlSetUniformMatrix(material.shader.locs[SHADER_LOC_MATRIX_PROJECTION], rlGetMatrixProjection());
 
-    // At this point the modelview matrix just contains the view matrix (camera)
-    // That's because BeginMode3D() sets it an no model-drawing function modifies it, all use rlPushMatrix() and rlPopMatrix()
-    Matrix matView = rlGetMatrixModelview();         // View matrix (camera)
-    Matrix matProjection = rlGetMatrixProjection();  // Projection matrix (perspective)
+    bool instancing = false;
+    if (instances < 1) return;
+    else if (instances > 1) instancing = true;
+    
+    float16 *instanceTransforms = NULL;
+    unsigned int instancesVboId = 0;
+    
+    Matrix matView = MatrixIdentity();
+    Matrix matModelView = MatrixIdentity();
+    Matrix matProjection = MatrixIdentity();
+    
+    if (instancing)
+    {
+        // Create instances buffer
+        instanceTransforms = RL_MALLOC(instances*sizeof(float16));
 
-    // Accumulate several transformations:
-    //    matView: rlgl internal modelview matrix (actually, just view matrix)
-    //    rlGetMatrixTransform(): rlgl internal transform matrix due to push/pop matrix stack
-    //    transform: function parameter transformation
-    Matrix matModelView = MatrixMultiply(transform, MatrixMultiply(rlGetMatrixTransform(), matView));
+        for (int i = 0; i < instances; i++) instanceTransforms[i] = MatrixToFloatV(transforms[i]);
+
+        // Enable mesh VAO to attach new buffer
+        rlEnableVertexArray(mesh.vaoId);
+
+        // This could alternatively use a static VBO and either glMapBuffer() or glBufferSubData().
+        // It isn't clear which would be reliably faster in all cases and on all platforms,
+        // anecdotally glMapBuffer() seems very slow (syncs) while glBufferSubData() seems 
+        // no faster, since we're transferring all the transform matrices anyway
+        instancesVboId = rlLoadVertexBuffer(instanceTransforms, instances*sizeof(float16), false);
+
+        // Instances are send to attribute location: SHADER_LOC_MATRIX_MODEL
+        unsigned int instanceLoc = material.shader.locs[SHADER_LOC_MATRIX_MODEL];
+
+        for (unsigned int i = 0; i < 4; i++)
+        {
+            rlEnableVertexAttribute(instanceLoc + i);
+            rlSetVertexAttribute(instanceLoc + i, 4, RL_FLOAT, 0, sizeof(Matrix), (void *)(i*sizeof(Vector4)));
+            
+            rlSetVertexAttributeDivisor(instanceLoc + i, 1);
+        }
+
+        rlDisableVertexBuffer();
+        rlDisableVertexArray();
+    }
+    else
+    {
+        // Calculate and send to shader model matrix
+        if (material.shader.locs[SHADER_LOC_MATRIX_MODEL] != -1) rlSetUniformMatrix(material.shader.locs[SHADER_LOC_MATRIX_MODEL], transforms[0]);
+
+        // At this point the modelview matrix just contains the view matrix (camera)
+        // That's because BeginMode3D() sets it an no model-drawing function modifies it, all use rlPushMatrix() and rlPopMatrix()
+        matView = rlGetMatrixModelview();         // View matrix (camera)
+        matProjection = rlGetMatrixProjection();  // Projection matrix (perspective)
+
+        // Accumulate several transformations:
+        //    matView: rlgl internal modelview matrix (actually, just view matrix)
+        //    rlGetMatrixTransform(): rlgl internal transform matrix due to push/pop matrix stack
+        //    transform: function parameter transformation
+        matModelView = MatrixMultiply(transforms[0], MatrixMultiply(rlGetMatrixTransform(), matView));
+    }
     //-----------------------------------------------------
 
     // Bind active texture maps (if available)
@@ -1092,16 +1139,15 @@ void DrawMesh(Mesh mesh, Material material, Matrix transform)
         if (mesh.indices != NULL) rlEnableVertexBufferElement(mesh.vboId[6]);
     }
     
-    //rlDrawVertexData(int vertexCount, Matrix matModelView, bool stereo)
-
     int eyesCount = 1;
-    //if (RLGL.State.stereoRender) eyesCount = 2;
+    // TODO: if (RLGL.State.stereoRender) eyesCount = 2;
 
     for (int eye = 0; eye < eyesCount; eye++)
     {
         if (eyesCount == 1) rlSetMatrixModelview(matModelView);
         else
         {
+            // TODO.
             // Setup current eye viewport (half screen width)
             //rlViewport(eye*rlGetFramebufferWidth()/2, 0, rlGetFramebufferWidth()/2, rlGetFramebufferHeight());
 
@@ -1111,16 +1157,23 @@ void DrawMesh(Mesh mesh, Material material, Matrix transform)
             // Set current eye projection matrix
             //rlSetMatrixProjection(RLGL.State.projectionStereo[eye]);
         }
-
+        
         // Calculate model-view-projection matrix (MVP)
-        Matrix matMVP = MatrixMultiply(rlGetMatrixModelview(), rlGetMatrixProjection());    // Transform to screen-space coordinates
-
+        Matrix matMVP = MatrixMultiply(rlGetMatrixModelview(), rlGetMatrixProjection());
+            
         // Send combined model-view-projection matrix to shader
         rlSetUniformMatrix(material.shader.locs[SHADER_LOC_MATRIX_MVP], matMVP);
 
-        // Draw calls
-        if (mesh.indices != NULL) rlDrawVertexArrayElements(0, mesh.triangleCount*3, 0);
-        else rlDrawVertexArray(0, mesh.vertexCount);
+        if (instancing) // Draw mesh instanced
+        {
+            if (mesh.indices != NULL) rlDrawVertexArrayElementsInstanced(0, mesh.triangleCount*3, 0, instances);
+            else rlDrawVertexArrayInstanced(0, mesh.vertexCount, instances);
+        }
+        else    // Draw mesh
+        {
+            if (mesh.indices != NULL) rlDrawVertexArrayElements(0, mesh.triangleCount*3, 0);
+            else rlDrawVertexArray(0, mesh.vertexCount);
+        }
     }
 
     // Unbind all binded texture maps
@@ -1144,9 +1197,18 @@ void DrawMesh(Mesh mesh, Material material, Matrix transform)
     // Disable shader program
     rlDisableShader();
 
-    // Restore rlgl internal modelview and projection matrices
-    rlSetMatrixModelview(matView);
-    rlSetMatrixProjection(matProjection);
+    if (instancing)
+    {
+        // Remove instance transforms buffer
+        rlUnloadVertexBuffer(instancesVboId);
+        RL_FREE(instanceTransforms);
+    }
+    else
+    {
+        // Restore rlgl internal modelview and projection matrices
+        rlSetMatrixModelview(matView);
+        rlSetMatrixProjection(matProjection);
+    }
 #endif
 }
 

src/raylib.h

@@ -1377,8 +1377,8 @@ RLAPI void UnloadModelKeepMeshes(Model model);
 
 // Mesh loading/unloading functions
 RLAPI void UploadMesh(Mesh *mesh, bool dynamic);                                            // Upload vertex data into GPU and provided VAO/VBO ids
-RLAPI void DrawMesh(Mesh mesh, Material material, Matrix transform);                        // Draw a 3d mesh with material and transform
-RLAPI void DrawMeshInstanced(Mesh mesh, Material material, Matrix *transforms, int count);  // Draw a 3d mesh with material and transform
+RLAPI void DrawMesh(Mesh mesh, Material material, Matrix transform);                       // Draw a 3d mesh with material and transform
+RLAPI void DrawMeshInstanced(Mesh mesh, Material material, Matrix *transforms, int instances); // Draw multiple mesh instances with material and different transforms
 RLAPI void UnloadMesh(Mesh mesh);                                                           // Unload mesh data from CPU and GPU
 RLAPI bool ExportMesh(Mesh mesh, const char *fileName);                                     // Export mesh data to file, returns true on success
 

src/rlgl.h

@@ -600,9 +600,12 @@ RLAPI void rlUpdateVertexBuffer(int bufferId, void *data, int dataSize, int offs
 RLAPI void rlUnloadVertexArray(unsigned int vaoId);
 RLAPI void rlUnloadVertexBuffer(unsigned int vboId);
 RLAPI void rlSetVertexAttribute(unsigned int index, int compSize, int type, bool normalized, int stride, void *pointer);
+RLAPI void rlSetVertexAttributeDivisor(unsigned int index, int divisor);
 RLAPI void rlSetVertexAttributeDefault(int locIndex, const void *value, int attribType, int count); // Set vertex attribute default value
 RLAPI void rlDrawVertexArray(int offset, int count);
 RLAPI void rlDrawVertexArrayElements(int offset, int count, void *buffer);
+RLAPI void rlDrawVertexArrayInstanced(int offset, int count, int instances);
+RLAPI void rlDrawVertexArrayElementsInstanced(int offset, int count, void *buffer, int instances);
 
 // Textures management
 RLAPI unsigned int rlLoadTexture(void *data, int width, int height, int format, int mipmapCount); // Load texture in GPU
@@ -3118,6 +3121,20 @@ void rlDrawVertexArrayElements(int offset, int count, void *buffer)
     glDrawElements(GL_TRIANGLES, count, GL_UNSIGNED_SHORT, buffer + offset);
 }
 
+void rlDrawVertexArrayInstanced(int offset, int count, int instances)
+{
+#if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
+    glDrawArraysInstanced(GL_TRIANGLES, 0, count, instances);
+#endif
+}
+
+void rlDrawVertexArrayElementsInstanced(int offset, int count, void *buffer, int instances)
+{
+#if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
+    glDrawElementsInstanced(GL_TRIANGLES, count, GL_UNSIGNED_SHORT, buffer + offset, instances);
+#endif
+}
+
 #if defined(GRAPHICS_API_OPENGL_11)
 void rlEnableStatePointer(int vertexAttribType, void *buffer)
 {
@@ -3155,6 +3172,13 @@ void rlSetVertexAttribute(unsigned int index, int compSize, int type, bool norma
 #endif
 }
 
+void rlSetVertexAttributeDivisor(unsigned int index, int divisor)
+{
+#if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
+    glVertexAttribDivisor(index, divisor);
+#endif
+}
+
 void rlUnloadVertexArray(unsigned int vaoId)
 {
 #if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
@@ -3171,7 +3195,7 @@ void rlUnloadVertexBuffer(unsigned int vboId)
 {
 #if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
     glDeleteBuffers(1, &vboId);
-    TRACELOG(LOG_INFO, "VBO: Unloaded vertex data from VRAM (GPU)");
+    o">//TRACELOG(LOG_INFO, "VBO: Unloaded vertex data from VRAM (GPU)");
 #endif
 }