+
+/**
+ * Return the number of per-buffer blend states to update in
+ * glBlendFunc, glBlendFuncSeparate, glBlendEquation, etc.
+ */
+static inline unsigned
+num_buffers(const struct gl_context *ctx)
+{
+ return ctx->Extensions.ARB_draw_buffers_blend
+ ? ctx->Const.MaxDrawBuffers : 1;
+}
+
+
+/* Returns true if there was no change */
+static bool
+skip_blend_state_update(const struct gl_context *ctx,
+ GLenum sfactorRGB, GLenum dfactorRGB,
+ GLenum sfactorA, GLenum dfactorA)
+{
+ /* Check if we're really changing any state. If not, return early. */
+ if (ctx->Color._BlendFuncPerBuffer) {
+ const unsigned numBuffers = num_buffers(ctx);
+
+ /* Check all per-buffer states */
+ for (unsigned buf = 0; buf < numBuffers; buf++) {
+ if (ctx->Color.Blend[buf].SrcRGB != sfactorRGB ||
+ ctx->Color.Blend[buf].DstRGB != dfactorRGB ||
+ ctx->Color.Blend[buf].SrcA != sfactorA ||
+ ctx->Color.Blend[buf].DstA != dfactorA) {
+ return false;
+ }
+ }
+ }
+ else {
+ /* only need to check 0th per-buffer state */
+ if (ctx->Color.Blend[0].SrcRGB != sfactorRGB ||
+ ctx->Color.Blend[0].DstRGB != dfactorRGB ||
+ ctx->Color.Blend[0].SrcA != sfactorA ||
+ ctx->Color.Blend[0].DstA != dfactorA) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+
+static void
+blend_func_separate(struct gl_context *ctx,
+ GLenum sfactorRGB, GLenum dfactorRGB,
+ GLenum sfactorA, GLenum dfactorA)
+{
+ FLUSH_VERTICES(ctx, ctx->DriverFlags.NewBlend ? 0 : _NEW_COLOR);
+ ctx->NewDriverState |= ctx->DriverFlags.NewBlend;
+
+ const unsigned numBuffers = num_buffers(ctx);
+ for (unsigned buf = 0; buf < numBuffers; buf++) {
+ ctx->Color.Blend[buf].SrcRGB = sfactorRGB;
+ ctx->Color.Blend[buf].DstRGB = dfactorRGB;
+ ctx->Color.Blend[buf].SrcA = sfactorA;
+ ctx->Color.Blend[buf].DstA = dfactorA;
+ }
+
+ update_uses_dual_src(ctx, 0);
+ for (unsigned buf = 1; buf < numBuffers; buf++) {
+ ctx->Color.Blend[buf]._UsesDualSrc = ctx->Color.Blend[0]._UsesDualSrc;
+ }
+
+ ctx->Color._BlendFuncPerBuffer = GL_FALSE;
+
+ if (ctx->Driver.BlendFuncSeparate) {
+ ctx->Driver.BlendFuncSeparate(ctx, sfactorRGB, dfactorRGB,
+ sfactorA, dfactorA);
+ }
+}
+
+
+/**
+ * Specify the blending operation.
+ *
+ * \param sfactor source factor operator.
+ * \param dfactor destination factor operator.
+ *
+ * \sa glBlendFunc, glBlendFuncSeparateEXT
+ */
+void GLAPIENTRY
+_mesa_BlendFunc( GLenum sfactor, GLenum dfactor )
+{
+ GET_CURRENT_CONTEXT(ctx);
+
+ if (skip_blend_state_update(ctx, sfactor, dfactor, sfactor, dfactor))
+ return;
+
+ if (!validate_blend_factors(ctx, "glBlendFunc",
+ sfactor, dfactor, sfactor, dfactor)) {
+ return;
+ }
+
+ blend_func_separate(ctx, sfactor, dfactor, sfactor, dfactor);
+}
+
+
+void GLAPIENTRY
+_mesa_BlendFunc_no_error(GLenum sfactor, GLenum dfactor)
+{
+ GET_CURRENT_CONTEXT(ctx);
+
+ if (skip_blend_state_update(ctx, sfactor, dfactor, sfactor, dfactor))
+ return;
+
+ blend_func_separate(ctx, sfactor, dfactor, sfactor, dfactor);
+}
+
+