From 03d848ea1003abefd8fe51a5b4a780527cd852af Mon Sep 17 00:00:00 2001 From: =?utf8?q?Marek=20Ol=C5=A1=C3=A1k?= Date: Wed, 4 Dec 2013 00:27:20 +0100 Subject: [PATCH] mesa: fix interpretation of glClearBuffer(drawbuffer) This corresponding piglit tests supported this incorrect behavior instead of pointing at it. Reviewed-by: Ian Romanick Cc: 10.0 9.2 9.1 --- src/mesa/main/clear.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/src/mesa/main/clear.c b/src/mesa/main/clear.c index 304d135d14e..f0b525fa017 100644 --- a/src/mesa/main/clear.c +++ b/src/mesa/main/clear.c @@ -219,7 +219,25 @@ make_color_buffer_mask(struct gl_context *ctx, GLint drawbuffer) const struct gl_renderbuffer_attachment *att = ctx->DrawBuffer->Attachment; GLbitfield mask = 0x0; - switch (drawbuffer) { + /* From the GL 4.0 specification: + * If buffer is COLOR, a particular draw buffer DRAW_BUFFERi is + * specified by passing i as the parameter drawbuffer, and value + * points to a four-element vector specifying the R, G, B, and A + * color to clear that draw buffer to. If the draw buffer is one + * of FRONT, BACK, LEFT, RIGHT, or FRONT_AND_BACK, identifying + * multiple buffers, each selected buffer is cleared to the same + * value. + * + * Note that "drawbuffer" and "draw buffer" have different meaning. + * "drawbuffer" specifies DRAW_BUFFERi, while "draw buffer" is what's + * assigned to DRAW_BUFFERi. It could be COLOR_ATTACHMENT0, FRONT, BACK, + * etc. + */ + if (drawbuffer < 0 || drawbuffer >= (GLint)ctx->Const.MaxDrawBuffers) { + return INVALID_MASK; + } + + switch (ctx->DrawBuffer->ColorDrawBuffer[drawbuffer]) { case GL_FRONT: if (att[BUFFER_FRONT_LEFT].Renderbuffer) mask |= BUFFER_BIT_FRONT_LEFT; @@ -255,11 +273,12 @@ make_color_buffer_mask(struct gl_context *ctx, GLint drawbuffer) mask |= BUFFER_BIT_BACK_RIGHT; break; default: - if (drawbuffer < 0 || drawbuffer >= (GLint)ctx->Const.MaxDrawBuffers) { - mask = INVALID_MASK; - } - else if (att[BUFFER_COLOR0 + drawbuffer].Renderbuffer) { - mask |= (BUFFER_BIT_COLOR0 << drawbuffer); + { + GLuint buf = ctx->DrawBuffer->_ColorDrawBufferIndexes[drawbuffer]; + + if (buf >= 0 && att[buf].Renderbuffer) { + mask |= 1 << buf; + } } } -- 2.30.2