Merge pull request #1104 from Subv/instanced_arrays

GLRasterizer: Implemented instanced vertex arrays.

2 files changed, 30 insertions, 4 deletions

diff --git a/src/video_core/engines/maxwell_3d.h b/src/video_core/engines/maxwell_3d.h
index 771eb5abc..3c869d3a1 100644
--- a/src/video_core/engines/maxwell_3d.h
+++ b/src/video_core/engines/maxwell_3d.h
@@ -679,7 +679,19 @@ public:
 
                 INSERT_PADDING_WORDS(0x7);
 
-                INSERT_PADDING_WORDS(0x46);
+                INSERT_PADDING_WORDS(0x20);
+
+                struct {
+                    u32 is_instanced[NumVertexArrays];
+
+                    /// Returns whether the vertex array specified by index is supposed to be
+                    /// accessed per instance or not.
+                    bool IsInstancingEnabled(u32 index) const {
+                        return is_instanced[index];
+                    }
+                } instanced_arrays;
+
+                INSERT_PADDING_WORDS(0x6);
 
                 Cull cull;
 
@@ -928,6 +940,7 @@ ASSERT_REG_POSITION(point_coord_replace, 0x581);
 ASSERT_REG_POSITION(code_address, 0x582);
 ASSERT_REG_POSITION(draw, 0x585);
 ASSERT_REG_POSITION(index_array, 0x5F2);
+ASSERT_REG_POSITION(instanced_arrays, 0x620);
 ASSERT_REG_POSITION(cull, 0x646);
 ASSERT_REG_POSITION(clear_buffers, 0x674);
 ASSERT_REG_POSITION(query, 0x6C0);
diff --git a/src/video_core/renderer_opengl/gl_rasterizer.cpp b/src/video_core/renderer_opengl/gl_rasterizer.cpp
index 93eadde7a..fe1f55e85 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.cpp
+++ b/src/video_core/renderer_opengl/gl_rasterizer.cpp
@@ -98,7 +98,8 @@ RasterizerOpenGL::~RasterizerOpenGL() {}
 std::pair<u8*, GLintptr> RasterizerOpenGL::SetupVertexArrays(u8* array_ptr,
                                                              GLintptr buffer_offset) {
     MICROPROFILE_SCOPE(OpenGL_VAO);
-    const auto& regs = Core::System::GetInstance().GPU().Maxwell3D().regs;
+    const auto& gpu = Core::System::GetInstance().GPU().Maxwell3D();
+    const auto& regs = gpu.regs;
 
     state.draw.vertex_array = hw_vao.handle;
     state.draw.vertex_buffer = stream_buffer.GetHandle();
@@ -110,9 +111,13 @@ std::pair<u8*, GLintptr> RasterizerOpenGL::SetupVertexArrays(u8* array_ptr,
         if (!vertex_array.IsEnabled())
             continue;
 
-        const Tegra::GPUVAddr start = vertex_array.StartAddress();
+        Tegra::GPUVAddr start = vertex_array.StartAddress();
         const Tegra::GPUVAddr end = regs.vertex_array_limit[index].LimitAddress();
 
+        if (regs.instanced_arrays.IsInstancingEnabled(index) && vertex_array.divisor != 0) {
+            start += vertex_array.stride * (gpu.state.current_instance / vertex_array.divisor);
+        }
+
         ASSERT(end > start);
         u64 size = end - start + 1;
 
@@ -124,7 +129,15 @@ std::pair<u8*, GLintptr> RasterizerOpenGL::SetupVertexArrays(u8* array_ptr,
         glBindVertexBuffer(index, stream_buffer.GetHandle(), vertex_buffer_offset,
                            vertex_array.stride);
 
-        ASSERT_MSG(vertex_array.divisor == 0, "Instanced vertex arrays are not supported");
+        if (regs.instanced_arrays.IsInstancingEnabled(index) && vertex_array.divisor != 0) {
+            // Tell OpenGL that this is an instanced vertex buffer to prevent accessing different
+            // indexes on each vertex. We do the instance indexing manually by incrementing the
+            // start address of the vertex buffer.
+            glVertexBindingDivisor(index, 1);
+        } else {
+            // Disable the vertex buffer instancing.
+            glVertexBindingDivisor(index, 0);
+        }
     }
 
     // Use the vertex array as-is, assumes that the data is formatted correctly for OpenGL.