GPUState: Only apply state before drawing

Referenced by commit f12b0373f3, BGL: Workaround broken bgl usage caused by GPU refactor
Referenced by issue #81289, Python gpu bgl image drawing alpha problem
Referenced by issue #80169, Node wrangler highlighting artifacts

source/blender/gpu/intern/gpu_batch.cc

@@ -282,6 +282,8 @@ void GPU_batch_draw_advanced(GPUBatch *batch, int v_first, int v_count, int i_fi
 /* just draw some vertices and let shader place them where we want. */
 void GPU_draw_primitive(GPUPrimType prim_type, int v_count)
 {
+  GPU_context_active_get()->state_manager->apply_state();
+
   /* we cannot draw without vao ... annoying ... */
   glBindVertexArray(GPU_vao_default());
 

source/blender/gpu/intern/gpu_framebuffer.cc

@@ -622,6 +622,8 @@ void GPU_framebuffer_clear(GPUFrameBuffer *fb,
 {
   CHECK_FRAMEBUFFER_IS_BOUND(fb);
 
+  GPU_context_active_get()->state_manager->apply_state();
+
   if (buffers & GPU_COLOR_BIT) {
     glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
     glClearColor(clear_col[0], clear_col[1], clear_col[2], clear_col[3]);
@@ -786,6 +788,8 @@ void GPU_framebuffer_blit(GPUFrameBuffer *fb_read,
 
   GLbitfield mask = convert_buffer_bits_to_gl(blit_buffers);
 
+  GPU_context_active_get()->state_manager->apply_state();
+
   glBlitFramebuffer(0,
                     0,
                     fb_read->width,
@@ -1043,6 +1047,8 @@ void GPU_offscreen_draw_to_screen(GPUOffScreen *ofs, int x, int y)
   const int w = GPU_texture_width(ofs->color);
   const int h = GPU_texture_height(ofs->color);
 
+  GPU_context_active_get()->state_manager->apply_state();
+
   GPUFrameBuffer *ofs_fb = gpu_offscreen_fb_get(ofs);
 
   glBindFramebuffer(GL_READ_FRAMEBUFFER, ofs_fb->object);
@@ -1107,6 +1113,7 @@ void GPU_clear_depth(float depth)
 
 void GPU_clear(eGPUFrameBufferBits flags)
 {
+  GPU_context_active_get()->state_manager->apply_state();
   glClear(convert_buffer_bits_to_gl(flags));
 }
 

source/blender/gpu/intern/gpu_immediate.cc

@@ -210,6 +210,8 @@ static bool vertex_count_makes_sense_for_primitive(uint vertex_len, GPUPrimType
 
 void immBegin(GPUPrimType prim_type, uint vertex_len)
 {
+  GPU_context_active_get()->state_manager->apply_state();
+
 #if TRUST_NO_ONE
   assert(initialized);
   assert(imm.prim_type == GPU_PRIM_NONE); /* make sure we haven't already begun */

source/blender/gpu/intern/gpu_state.cc

@@ -45,8 +45,6 @@ using namespace blender::gpu;
     GPUStateManager *stack = GPU_context_active_get()->state_manager; \
     auto &state_object = stack->_prefix##state; \
     state_object._state = _value; \
-    /* TODO remove this and only push state at draw time. */ \
-    stack->set_##_prefix##state(state_object); \
   } while (0)
 
 #define SET_IMMUTABLE_STATE(_state, _value) SET_STATE(, _state, _value)
@@ -112,8 +110,6 @@ void GPU_color_mask(bool r, bool g, bool b, bool a)
   SET_FLAG_FROM_TEST(write_mask, b, GPU_WRITE_BLUE);
   SET_FLAG_FROM_TEST(write_mask, a, GPU_WRITE_ALPHA);
   state.write_mask = write_mask;
-  /* TODO remove this and only push state at draw time. */
-  stack->set_state(state);
 }
 
 void GPU_depth_mask(bool depth)
@@ -123,8 +119,6 @@ void GPU_depth_mask(bool depth)
   eGPUWriteMask write_mask = state.write_mask;
   SET_FLAG_FROM_TEST(write_mask, depth, GPU_WRITE_DEPTH);
   state.write_mask = write_mask;
-  /* TODO remove this and only push state at draw time. */
-  stack->set_state(state);
 }
 
 void GPU_clip_distances(int distances_enabled)
@@ -143,8 +137,6 @@ void GPU_depth_range(float near, float far)
   GPUStateManager *stack = GPU_context_active_get()->state_manager;
   auto &state = stack->mutable_state;
   copy_v2_fl2(state.depth_range, near, far);
-  /* TODO remove this and only push state at draw time. */
-  stack->set_mutable_state(state);
 }
 
 void GPU_line_width(float width)
@@ -167,8 +159,6 @@ void GPU_program_point_size(bool enable)
   auto &state = stack->mutable_state;
   /* Set point size sign negative to disable. */
   state.point_size = fabsf(state.point_size) * (enable ? 1 : -1);
-  /* TODO remove this and only push state at draw time. */
-  stack->set_mutable_state(state);
 }
 
 void GPU_scissor_test(bool enable)
@@ -177,8 +167,6 @@ void GPU_scissor_test(bool enable)
   auto &state = stack->mutable_state;
   /* Set point size sign negative to disable. */
   state.scissor_rect[2] = abs(state.scissor_rect[2]) * (enable ? 1 : -1);
-  /* TODO remove this and only push state at draw time. */
-  stack->set_mutable_state(state);
 }
 
 void GPU_scissor(int x, int y, int width, int height)
@@ -187,8 +175,6 @@ void GPU_scissor(int x, int y, int width, int height)
   auto &state = stack->mutable_state;
   int scissor_rect[4] = {x, y, width, height};
   copy_v4_v4_int(state.scissor_rect, scissor_rect);
-  /* TODO remove this and only push state at draw time. */
-  stack->set_mutable_state(state);
 }
 
 void GPU_viewport(int x, int y, int width, int height)
@@ -197,8 +183,6 @@ void GPU_viewport(int x, int y, int width, int height)
   auto &state = stack->mutable_state;
   int viewport_rect[4] = {x, y, width, height};
   copy_v4_v4_int(state.viewport_rect, viewport_rect);
-  /* TODO remove this and only push state at draw time. */
-  stack->set_mutable_state(state);
 }
 
 /** \} */

source/blender/gpu/intern/gpu_state_private.hh

@@ -138,6 +138,12 @@ class GPUStateManager {
 
   virtual void set_state(const GPUState &state) = 0;
   virtual void set_mutable_state(const GPUStateMutable &state) = 0;
+
+  inline void apply_state(void)
+  {
+    this->set_state(this->state);
+    this->set_mutable_state(this->mutable_state);
+  };
 };
 
 }  // namespace gpu

source/blender/gpu/opengl/gl_batch.cc

@@ -300,6 +300,8 @@ GLBatch::~GLBatch()
 
 void GLBatch::bind(int i_first)
 {
+  GPU_context_active_get()->state_manager->apply_state();
+
   if (flag & GPU_BATCH_DIRTY) {
     vao_cache_.clear();
   }

source/blender/gpu/opengl/gl_state.cc

@@ -102,9 +102,8 @@ void GLStateManager::set_mutable_state(const GPUStateMutable &state)
 
   if ((changed.scissor_rect[0] != 0) || (changed.scissor_rect[1] != 0) ||
       (changed.scissor_rect[2] != 0) || (changed.scissor_rect[3] != 0)) {
-    glScissor(UNPACK4(state.scissor_rect));
-
     if ((state.scissor_rect[2] > 0)) {
+      glScissor(UNPACK4(state.scissor_rect));
       glEnable(GL_SCISSOR_TEST);
     }
     else {