From d531f9c2f5c78468d913fc509b223760ac1c1124 Mon Sep 17 00:00:00 2001 From: Marek Olšák Date: Thu, 2 Dec 2010 20:39:59 +0100 Subject: mesa, st/mesa: fix gl_FragCoord with FBOs in Gallium MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit gl_FragCoord.y needs to be flipped upside down if a FBO is bound. This fixes: - piglit/fbo-fragcoord - https://bugs.freedesktop.org/show_bug.cgi?id=29420 Here I add a new program state STATE_FB_WPOS_Y_TRANSFORM, which is set based on whether a FBO is bound. The state contains a pair of transformations. It can be either (XY=identity, ZW=transformY) if a FBO is bound, or (XY=transformY, ZW=identity) otherwise, where identity = (1, 0), transformY = (-1, height-1). A classic driver (or st/mesa) may, based on some other state, choose whether to use XY or ZW, thus negate the conditional "if (is a FBO bound) ...". The reason for this is that a Gallium driver is allowed to only support WPOS relative to either the lower left or the upper left corner, so we must flip the Y axis accordingly again. (the "invert" parameter in emit_wpos_inversion) NOTE: This is a candidate for the 7.9 branch. Signed-off-by: Marek Olšák Signed-off-by: Brian Paul --- src/mesa/program/prog_statevars.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'src/mesa/program/prog_statevars.c') diff --git a/src/mesa/program/prog_statevars.c b/src/mesa/program/prog_statevars.c index baac29ff0d..83bd3727f3 100644 --- a/src/mesa/program/prog_statevars.c +++ b/src/mesa/program/prog_statevars.c @@ -572,6 +572,24 @@ _mesa_fetch_state(struct gl_context *ctx, const gl_state_index state[], value[3] = 0.0F; return; + case STATE_FB_WPOS_Y_TRANSFORM: + /* A driver may negate this conditional by using ZW swizzle + * instead of XY (based on e.g. some other state). */ + if (ctx->DrawBuffer->Name != 0) { + /* Identity (XY) followed by flipping Y upside down (ZW). */ + value[0] = 1.0F; + value[1] = 0.0F; + value[2] = -1.0F; + value[3] = (GLfloat) (ctx->DrawBuffer->Height - 1); + } else { + /* Flipping Y upside down (XY) followed by identity (ZW). */ + value[0] = -1.0F; + value[1] = (GLfloat) (ctx->DrawBuffer->Height - 1); + value[2] = 1.0F; + value[3] = 0.0F; + } + return; + case STATE_ROT_MATRIX_0: { const int unit = (int) state[2]; @@ -695,6 +713,7 @@ _mesa_program_state_flags(const gl_state_index state[STATE_LENGTH]) return _NEW_PIXEL; case STATE_FB_SIZE: + case STATE_FB_WPOS_Y_TRANSFORM: return _NEW_BUFFERS; default: @@ -900,6 +919,9 @@ append_token(char *dst, gl_state_index k) case STATE_FB_SIZE: append(dst, "FbSize"); break; + case STATE_FB_WPOS_Y_TRANSFORM: + append(dst, "FbWposYTransform"); + break; case STATE_ROT_MATRIX_0: append(dst, "rotMatrixRow0"); break; -- cgit v1.2.3