mesa: Check that draw buffers are valid for glDrawBuffers on GLES3

Section 4.2 (Whole Framebuffer Operations) of the OpenGL 3.0 specification
says:

    "Each buffer listed in bufs must be BACK, NONE, or one of the values from
     table 4.3 (NONE, COLOR_ATTACHMENTi)".

Fixes 1 dEQP test:
* dEQP-GLES3.functional.negative_api.buffer.draw_buffers

Reviewed-by: Matt Turner <[email protected]>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/mesa/main/buffers.c b/src/mesa/main/buffers.c
index a2d02d56154..e5076e9bbde 100644
--- a/src/mesa/main/buffers.c
+++ b/src/mesa/main/buffers.c
@@ -336,6 +336,20 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers)
 
    /* complicated error checking... */
    for (output = 0; output < n; output++) {
+      /* Section 4.2 (Whole Framebuffer Operations) of the OpenGL 3.0
+       * specification says:
+       *
+       *     "Each buffer listed in bufs must be BACK, NONE, or one of the values
+       *      from table 4.3 (NONE, COLOR_ATTACHMENTi)"
+       */
+      if (_mesa_is_gles3(ctx) && buffers[output] != GL_NONE &&
+          buffers[output] != GL_BACK &&
+          (buffers[output] < GL_COLOR_ATTACHMENT0 ||
+           buffers[output] >= GL_COLOR_ATTACHMENT0 + ctx->Const.MaxColorAttachments)) {
+         _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffers(buffer)");
+         return;
+      }
+
       if (buffers[output] == GL_NONE) {
          destMask[output] = 0x0;
       }