Adding the scissor rect in the Batch and a way to enable the scissor test locally for clear commands

libraries/gpu/src/gpu/Batch.cpp

@@ -102,9 +102,10 @@ void Batch::drawIndexedInstanced(uint32 nbInstances, Primitive primitiveType, ui
     _params.push_back(nbInstances);
 }
 
-void Batch::clearFramebuffer(Framebuffer::Masks targets, const Vec4& color, float depth, int stencil) {
+void Batch::clearFramebuffer(Framebuffer::Masks targets, const Vec4& color, float depth, int stencil, bool enableScissor) {
     ADD_COMMAND(clearFramebuffer);
 
+    _params.push_back(enableScissor);
     _params.push_back(stencil);
     _params.push_back(depth);
     _params.push_back(color.w);
@@ -114,20 +115,20 @@ void Batch::clearFramebuffer(Framebuffer::Masks targets, const Vec4& color, floa
     _params.push_back(targets);
 }
 
-void Batch::clearColorFramebuffer(Framebuffer::Masks targets, const Vec4& color) {
-    clearFramebuffer(targets & Framebuffer::BUFFER_COLORS, color, 1.0f, 0);
+void Batch::clearColorFramebuffer(Framebuffer::Masks targets, const Vec4& color, bool enableScissor) {
+    clearFramebuffer(targets & Framebuffer::BUFFER_COLORS, color, 1.0f, 0, enableScissor);
 }
 
-void Batch::clearDepthFramebuffer(float depth) {
-    clearFramebuffer(Framebuffer::BUFFER_DEPTH, Vec4(0.0f), depth, 0);
+void Batch::clearDepthFramebuffer(float depth, bool enableScissor) {
+    clearFramebuffer(Framebuffer::BUFFER_DEPTH, Vec4(0.0f), depth, 0, enableScissor);
 }
 
-void Batch::clearStencilFramebuffer(int stencil) {
-    clearFramebuffer(Framebuffer::BUFFER_STENCIL, Vec4(0.0f), 1.0f, stencil);
+void Batch::clearStencilFramebuffer(int stencil, bool enableScissor) {
+    clearFramebuffer(Framebuffer::BUFFER_STENCIL, Vec4(0.0f), 1.0f, stencil, enableScissor);
 }
 
-void Batch::clearDepthStencilFramebuffer(float depth, int stencil) {
-    clearFramebuffer(Framebuffer::BUFFER_DEPTHSTENCIL, Vec4(0.0f), depth, stencil);
+void Batch::clearDepthStencilFramebuffer(float depth, int stencil, bool enableScissor) {
+    clearFramebuffer(Framebuffer::BUFFER_DEPTHSTENCIL, Vec4(0.0f), depth, stencil, enableScissor);
 }
 
 

libraries/gpu/src/gpu/Batch.h

@@ -62,11 +62,12 @@ public:
 
     // Clear framebuffer layers
     // Targets can be any of the render buffers contained in the Framebuffer
-    void clearFramebuffer(Framebuffer::Masks targets, const Vec4& color, float depth, int stencil);
-    void clearColorFramebuffer(Framebuffer::Masks targets, const Vec4& color); // not a command, just a shortcut for clearFramebuffer, mask out targets to make sure it touches only color targets
-    void clearDepthFramebuffer(float depth); // not a command, just a shortcut for clearFramebuffer, it touches only depth target
-    void clearStencilFramebuffer(int stencil); // not a command, just a shortcut for clearFramebuffer, it touches only stencil target
-    void clearDepthStencilFramebuffer(float depth, int stencil); // not a command, just a shortcut for clearFramebuffer, it touches depth and stencil target
+    // Optionally the scissor test can be enabled locally for this command and to restrict the clearing command to the pixels contained in the scissor rectangle
+    void clearFramebuffer(Framebuffer::Masks targets, const Vec4& color, float depth, int stencil, bool enableScissor = false);
+    void clearColorFramebuffer(Framebuffer::Masks targets, const Vec4& color, bool enableScissor = false); // not a command, just a shortcut for clearFramebuffer, mask out targets to make sure it touches only color targets
+    void clearDepthFramebuffer(float depth, bool enableScissor = false); // not a command, just a shortcut for clearFramebuffer, it touches only depth target
+    void clearStencilFramebuffer(int stencil, bool enableScissor = false); // not a command, just a shortcut for clearFramebuffer, it touches only stencil target
+    void clearDepthStencilFramebuffer(float depth, int stencil, bool enableScissor = false); // not a command, just a shortcut for clearFramebuffer, it touches depth and stencil target
     
     // Input Stage
     // InputFormat
@@ -90,13 +91,18 @@ public:
     void setModelTransform(const Transform& model);
     void setViewTransform(const Transform& view);
     void setProjectionTransform(const Mat4& proj);
-    void setViewportTransform(const Vec4i& viewport); // Viewport is xy = low left corner in the framebuffer, zw = width height of the viewport
+    // Viewport is xy = low left corner in framebuffer, zw = width height of the viewport, expressed in pixels
+    void setViewportTransform(const Vec4i& viewport);
 
     // Pipeline Stage
     void setPipeline(const PipelinePointer& pipeline);
 
     void setStateBlendFactor(const Vec4& factor);
 
+    // Set the Scissor rect
+    // the rect coordinates are xy for the low left corner of the rect and zw for the width and height of the rect, expressed in pixels
+    void setStateScissorRect(const Vec4i& rect);
+
     void setUniformBuffer(uint32 slot, const BufferPointer& buffer, Offset offset, Offset size);
     void setUniformBuffer(uint32 slot, const BufferView& view); // not a command, just a shortcut from a BufferView
 
@@ -173,6 +179,7 @@ public:
 
         COMMAND_setPipeline,
         COMMAND_setStateBlendFactor,
+        COMMAND_setStateScissorRect,
 
         COMMAND_setUniformBuffer,
         COMMAND_setResourceTexture,

libraries/gpu/src/gpu/GLBackend.cpp

@@ -33,6 +33,7 @@ GLBackend::CommandCall GLBackend::_commandCalls[Batch::NUM_COMMANDS] =
 
     (&::gpu::GLBackend::do_setPipeline),
     (&::gpu::GLBackend::do_setStateBlendFactor),
+    (&::gpu::GLBackend::do_setStateScissorRect),
 
     (&::gpu::GLBackend::do_setUniformBuffer),
     (&::gpu::GLBackend::do_setResourceTexture),
@@ -217,14 +218,15 @@ void GLBackend::do_drawIndexedInstanced(Batch& batch, uint32 paramOffset) {
 
 void GLBackend::do_clearFramebuffer(Batch& batch, uint32 paramOffset) {
 
-    uint32 masks = batch._params[paramOffset + 6]._uint;
+    uint32 masks = batch._params[paramOffset + 7]._uint;
     Vec4 color;
-    color.x = batch._params[paramOffset + 5]._float;
-    color.y = batch._params[paramOffset + 4]._float;
-    color.z = batch._params[paramOffset + 3]._float;
-    color.w = batch._params[paramOffset + 2]._float;
-    float depth = batch._params[paramOffset + 1]._float;
-    int stencil = batch._params[paramOffset + 0]._float;
+    color.x = batch._params[paramOffset + 6]._float;
+    color.y = batch._params[paramOffset + 5]._float;
+    color.z = batch._params[paramOffset + 4]._float;
+    color.w = batch._params[paramOffset + 3]._float;
+    float depth = batch._params[paramOffset + 2]._float;
+    int stencil = batch._params[paramOffset + 1]._int;
+    int useScissor = batch._params[paramOffset + 0]._int;
 
     GLuint glmask = 0;
     if (masks & Framebuffer::BUFFER_DEPTH) {
@@ -252,8 +254,19 @@ void GLBackend::do_clearFramebuffer(Batch& batch, uint32 paramOffset) {
         }
     }
 
+    // Apply scissor if needed and if not already on
+    bool doEnableScissor = (useScissor && (!_pipeline._stateCache.scissorEnable));
+    if (doEnableScissor) {
+        glEnable(GL_SCISSOR_TEST);
+    }
+
     glClear(glmask);
 
+    // Restore scissor if needed
+    if (doEnableScissor) {
+        glDisable(GL_SCISSOR_TEST);
+    }
+
     // Restore the color draw buffers only if a frmaebuffer is bound
     if (_output._framebuffer && !drawBuffers.empty()) {
         auto glFramebuffer = syncGPUObject(*_output._framebuffer);

libraries/gpu/src/gpu/GLBackend.h

@@ -350,6 +350,7 @@ protected:
     // Pipeline Stage
     void do_setPipeline(Batch& batch, uint32 paramOffset);
     void do_setStateBlendFactor(Batch& batch, uint32 paramOffset);
+    void do_setStateScissorRect(Batch& batch, uint32 paramOffset);
     
     // Standard update pipeline check that the current Program and current State or good to go for a
     void updatePipeline();

libraries/gpu/src/gpu/GLBackendState.cpp

@@ -753,3 +753,14 @@ void GLBackend::do_setStateBlendFactor(Batch& batch, uint32 paramOffset) {
     glBlendColor(factor.x, factor.y, factor.z, factor.w);
     (void) CHECK_GL_ERROR();
 }
+
+void GLBackend::do_setStateScissorRect(Batch& batch, uint32 paramOffset) {
+    
+    Vec4 rect(batch._params[paramOffset + 0]._float,
+                batch._params[paramOffset + 1]._float,
+                batch._params[paramOffset + 2]._float,
+                batch._params[paramOffset + 3]._float);
+
+    glScissor(rect.x, rect.y, rect.z, rect.w);
+    (void) CHECK_GL_ERROR();
+}