main: Refactor DrawBuffers.

This could have added a new DD table entry for DrawBuffers that takes an
arbitrary draw buffer, but, after looking at the existing DD functions,
Kenneth Graunke recommended that we just skip calling the DD functions in the
case of ARB_direct_state_access.  The DD implementations for DrawBuffer(s)
have limited functionality, especially with respect to
ARB_direct_state_access.

[Fredrik: Call the driver function when fb is the bound draw buffer]

Reviewed-by: Fredrik Höglund <fredrik@kde.org>
Signed-off-by: Fredrik Höglund <fredrik@kde.org>

2 files changed, 52 insertions, 23 deletions

diff --git a/src/mesa/main/buffers.c b/src/mesa/main/buffers.c
index d9979ad9ed..0c6d379309 100644
--- a/src/mesa/main/buffers.c
+++ b/src/mesa/main/buffers.c
@@ -325,13 +325,13 @@ _mesa_NamedFramebufferDrawBuffer(GLuint framebuffer, GLenum buf)
  *                 names cannot specify more than one buffer.  For example,
  *                 GL_FRONT_AND_BACK is illegal.
  */
-void GLAPIENTRY
-_mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
+void
+_mesa_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb,
+                   GLsizei n, const GLenum *buffers, const char *caller)
 {
    GLuint output;
    GLbitfield usedBufferMask, supportedMask;
    GLbitfield destMask[MAX_DRAW_BUFFERS];
-   GET_CURRENT_CONTEXT(ctx);
 
    FLUSH_VERTICES(ctx, 0);
 
@@ -342,12 +342,18 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
     * "An INVALID_VALUE error is generated if n is greater than
     *  MAX_DRAW_BUFFERS."
     */
-   if (n < 0 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
-      _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
+   if (n < 0) {
+      _mesa_error(ctx, GL_INVALID_VALUE, "%s(n < 0)", caller);
       return;
    }
 
-   supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
+   if (n > (GLsizei) ctx->Const.MaxDrawBuffers) {
+      _mesa_error(ctx, GL_INVALID_VALUE,
+                  "%s(n > maximum number of draw buffers)", caller);
+      return;
+   }
+
+   supportedMask = supported_buffer_bitmask(ctx, fb);
    usedBufferMask = 0x0;
 
    /* From the ES 3.0 specification, page 180:
@@ -355,9 +361,9 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
     *  and the constant must be BACK or NONE."
     * (same restriction applies with GL_EXT_draw_buffers specification)
     */
-   if (ctx->API == API_OPENGLES2 && _mesa_is_winsys_fbo(ctx->DrawBuffer) &&
+   if (ctx->API == API_OPENGLES2 && _mesa_is_winsys_fbo(fb) &&
        (n != 1 || (buffers[0] != GL_NONE && buffers[0] != GL_BACK))) {
-      _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffers(buffer)");
+      _mesa_error(ctx, GL_INVALID_OPERATION, "%s(invalid buffers)", caller);
       return;
    }
 
@@ -389,9 +395,11 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
           *     or equal to the value of MAX_COLOR_ATTACHMENTS, then the error
           *     INVALID_OPERATION results."
           */
-         if (_mesa_is_user_fbo(ctx->DrawBuffer) && buffers[output] >=
+         if (_mesa_is_user_fbo(fb) && buffers[output] >=
              GL_COLOR_ATTACHMENT0 + ctx->Const.MaxDrawBuffers) {
-            _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB(buffer)");
+            _mesa_error(ctx, GL_INVALID_OPERATION,
+                        "%s(buffers[%d] >= maximum number of draw buffers)",
+                        caller, output);
             return;
          }
 
@@ -402,9 +410,10 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
           *  4.5 or 4.6.  Otherwise, an INVALID_ENUM error is generated.
           */
          if (destMask[output] == BAD_MASK) {
-            _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
+            _mesa_error(ctx, GL_INVALID_ENUM, "%s(invalid buffer %s)",
+                        caller, _mesa_lookup_enum_by_nr(buffers[output]));
             return;
-         }         
+         }
 
          /* From the OpenGL 4.0 specification, page 256:
           * "For both the default framebuffer and framebuffer objects, the
@@ -417,7 +426,8 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
           *  but the Khronos conformance tests expect INVALID_ENUM.
           */
          if (_mesa_bitcount(destMask[output]) > 1) {
-            _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
+            _mesa_error(ctx, GL_INVALID_ENUM, "%s(invalid buffer %s)",
+                        caller, _mesa_lookup_enum_by_nr(buffers[output]));
             return;
          }
 
@@ -434,7 +444,8 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
          destMask[output] &= supportedMask;
          if (destMask[output] == 0) {
             _mesa_error(ctx, GL_INVALID_OPERATION,
-                        "glDrawBuffersARB(unsupported buffer)");
+                        "%s(unsupported buffer %s)",
+                        caller, _mesa_lookup_enum_by_nr(buffers[output]));
             return;
          }
 
@@ -443,10 +454,12 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
           *  in bufs must be COLOR_ATTACHMENTi or NONE. [...] INVALID_OPERATION."
           * (same restriction applies with GL_EXT_draw_buffers specification)
           */
-         if (ctx->API == API_OPENGLES2 && _mesa_is_user_fbo(ctx->DrawBuffer) &&
+         if (ctx->API == API_OPENGLES2 && _mesa_is_user_fbo(fb) &&
              buffers[output] != GL_NONE &&
              buffers[output] != GL_COLOR_ATTACHMENT0 + output) {
-            _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffers(buffer)");
+            _mesa_error(ctx, GL_INVALID_OPERATION,
+                        "%s(unsupported buffer %s)",
+                        caller, _mesa_lookup_enum_by_nr(buffers[output]));
             return;
          }
 
@@ -457,7 +470,8 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
           */
          if (destMask[output] & usedBufferMask) {
             _mesa_error(ctx, GL_INVALID_OPERATION,
-                        "glDrawBuffersARB(duplicated buffer)");
+                        "%s(duplicated buffer %s)",
+                        caller, _mesa_lookup_enum_by_nr(buffers[output]));
             return;
          }
 
@@ -467,17 +481,28 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
    }
 
    /* OK, if we get here, there were no errors so set the new state */
-   _mesa_drawbuffers(ctx, ctx->DrawBuffer, n, buffers, destMask);
+   _mesa_drawbuffers(ctx, fb, n, buffers, destMask);
 
    /*
-    * Call device driver function.  Note that n can be equal to 0,
+    * Call device driver function if fb is the bound draw buffer.
+    * Note that n can be equal to 0,
     * in which case we don't want to reference buffers[0], which
     * may not be valid.
     */
-   if (ctx->Driver.DrawBuffers)
-      ctx->Driver.DrawBuffers(ctx, n, buffers);
-   else if (ctx->Driver.DrawBuffer)
-      ctx->Driver.DrawBuffer(ctx, n > 0 ? buffers[0] : GL_NONE);
+   if (fb == ctx->DrawBuffer) {
+      if (ctx->Driver.DrawBuffers)
+         ctx->Driver.DrawBuffers(ctx, n, buffers);
+      else if (ctx->Driver.DrawBuffer)
+         ctx->Driver.DrawBuffer(ctx, n > 0 ? buffers[0] : GL_NONE);
+   }
+}
+
+
+void GLAPIENTRY
+_mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   _mesa_draw_buffers(ctx, ctx->DrawBuffer, n, buffers, "glDrawBuffers");
 }
 
 
diff --git a/src/mesa/main/buffers.h b/src/mesa/main/buffers.h
index 52a2318819..66871d70a0 100644
--- a/src/mesa/main/buffers.h
+++ b/src/mesa/main/buffers.h
@@ -48,6 +48,10 @@ _mesa_DrawBuffer( GLenum mode );
 extern void GLAPIENTRY
 _mesa_NamedFramebufferDrawBuffer(GLuint framebuffer, GLenum buf);
 
+extern void
+_mesa_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb,
+                   GLsizei n, const GLenum *buffers, const char *caller);
+
 extern void GLAPIENTRY
 _mesa_DrawBuffers(GLsizei n, const GLenum *buffers);