GPUState: Add GL backend and state tracking but do not use it

This is just the backend work. It is not plugged in yet because it
needs more external cleanup/refactor.

1 files changed, 69 insertions, 11 deletions

diff --git a/source/blender/gpu/GPU_state.h b/source/blender/gpu/GPU_state.h
index 2a940b97104..19bb8001491 100644
--- a/source/blender/gpu/GPU_state.h
+++ b/source/blender/gpu/GPU_state.h
@@ -24,6 +24,70 @@
 extern "C" {
 #endif
 
+typedef enum eGPUWriteMask {
+  GPU_WRITE_RED = (1 << 0),
+  GPU_WRITE_GREEN = (1 << 1),
+  GPU_WRITE_BLUE = (1 << 2),
+  GPU_WRITE_ALPHA = (1 << 3),
+  GPU_WRITE_DEPTH = (1 << 4),
+  GPU_WRITE_COLOR = (GPU_WRITE_RED | GPU_WRITE_GREEN | GPU_WRITE_BLUE | GPU_WRITE_ALPHA),
+} eGPUWriteMask;
+
+/**
+ * Defines the fixed pipeline blending equation.
+ * SRC is the output color from the shader.
+ * DST is the color from the framebuffer.
+ * The blending equation is :
+ *  (SRC * A) + (DST * B).
+ * The blend mode will modify the A and B parameters.
+ */
+typedef enum eGPUBlend {
+  GPU_BLEND_NONE = 0,
+  /** Premult variants will _NOT_ multiply rgb output by alpha. */
+  GPU_BLEND_ALPHA,
+  GPU_BLEND_ALPHA_PREMULT,
+  GPU_BLEND_ADDITIVE,
+  GPU_BLEND_ADDITIVE_PREMULT,
+  GPU_BLEND_MULTIPLY,
+  GPU_BLEND_SUBTRACT,
+  /** Replace logic op: SRC * (1 - DST)
+   * NOTE: Does not modify alpha. */
+  GPU_BLEND_INVERT,
+  /** Order independant transparency.
+   * NOTE: Cannot be used as is. Needs special setup (framebuffer, shader ...). */
+  GPU_BLEND_OIT,
+  /** Special blend to add color under and multiply dst color by src alpha. */
+  GPU_BLEND_BACKGROUND,
+  /** Custom blend parameters using dual source blending : SRC0 + SRC1 * DST
+   * NOTE: Can only be used with _ONE_ Draw Buffer and shader needs to be specialized. */
+  GPU_BLEND_CUSTOM,
+} eGPUBlend;
+
+typedef enum eGPUDepthTest {
+  GPU_DEPTH_NONE = 0,
+  GPU_DEPTH_ALWAYS,
+  GPU_DEPTH_LESS,
+  GPU_DEPTH_LESS_EQUAL,
+  GPU_DEPTH_EQUAL,
+  GPU_DEPTH_GREATER,
+  GPU_DEPTH_GREATER_EQUAL,
+} eGPUDepthTest;
+
+typedef enum eGPUStencilTest {
+  GPU_STENCIL_NONE = 0,
+  GPU_STENCIL_ALWAYS,
+  GPU_STENCIL_EQUAL,
+  GPU_STENCIL_NEQUAL,
+} eGPUStencilTest;
+
+typedef enum eGPUStencilOp {
+  GPU_STENCIL_OP_NONE = 0,
+  GPU_STENCIL_OP_REPLACE,
+  /** Special values for stencil shadows. */
+  GPU_STENCIL_OP_COUNT_DEPTH_PASS,
+  GPU_STENCIL_OP_COUNT_DEPTH_FAIL,
+} eGPUStencilOp;
+
 /* These map directly to the GL_ blend functions, to minimize API add as needed*/
 typedef enum eGPUBlendFunction {
   GPU_ONE,
@@ -33,21 +97,15 @@ typedef enum eGPUBlendFunction {
   GPU_ZERO,
 } eGPUBlendFunction;
 
-/* These map directly to the GL_ filter functions, to minimize API add as needed*/
-typedef enum eGPUFilterFunction {
-  GPU_NEAREST,
-  GPU_LINEAR,
-} eGPUFilterFunction;
-
-typedef enum eGPUFaceCull {
+typedef enum eGPUFaceCullTest {
   GPU_CULL_NONE = 0, /* Culling disabled. */
   GPU_CULL_FRONT,
   GPU_CULL_BACK,
-} eGPUFaceCull;
+} eGPUFaceCullTest;
 
 typedef enum eGPUProvokingVertex {
-  GPU_VERTEX_FIRST = 0,
-  GPU_VERTEX_LAST, /* Default */
+  GPU_VERTEX_LAST = 0,  /* Default. */
+  GPU_VERTEX_FIRST = 1, /* Follow Blender loop order. */
 } eGPUProvokingVertex;
 
 /* Initialize
@@ -62,7 +120,7 @@ void GPU_blend_set_func_separate(eGPUBlendFunction src_rgb,
                                  eGPUBlendFunction dst_rgb,
                                  eGPUBlendFunction src_alpha,
                                  eGPUBlendFunction dst_alpha);
-void GPU_face_culling(eGPUFaceCull culling);
+void GPU_face_culling(eGPUFaceCullTest culling);
 void GPU_front_facing(bool invert);
 void GPU_provoking_vertex(eGPUProvokingVertex vert);
 void GPU_depth_range(float near, float far);