diff options
| -rw-r--r-- | progs/trivial/tri-cull.c | 14 | ||||
| -rw-r--r-- | src/mesa/pipe/draw/draw_cull.c | 12 | ||||
| -rw-r--r-- | src/mesa/pipe/draw/draw_twoside.c | 12 | ||||
| -rw-r--r-- | src/mesa/state_tracker/st_atom_setup.c | 32 |
4 files changed, 46 insertions, 24 deletions
diff --git a/progs/trivial/tri-cull.c b/progs/trivial/tri-cull.c index af26cb0b2b..2eead84115 100644 --- a/progs/trivial/tri-cull.c +++ b/progs/trivial/tri-cull.c @@ -29,6 +29,7 @@ static GLenum doubleBuffer; static GLint cullmode = 0; +static GLenum front = GL_CCW; /* GL default */ static void cull(void) { @@ -76,11 +77,16 @@ static void Reshape(int width, int height) static void Key(unsigned char key, int x, int y) { switch (key) { - case 27: - exit(1); + case 27: + exit(1); case 'c': cull(); break; + case 'f': + front = ((front == GL_CCW) ? GL_CW : GL_CCW); + glFrontFace(front); + printf("front face = %s\n", front == GL_CCW ? "GL_CCW" : "GL_CW"); + break; default: return; } @@ -92,7 +98,7 @@ static void Draw(void) glClear(GL_COLOR_BUFFER_BIT); glBegin(GL_TRIANGLES); - /* back-facing */ + /* CCW / front-facing */ glColor3f(0,0,.7); glVertex3f(-0.1, -0.9, -30.0); glColor3f(.8,0,0); @@ -100,7 +106,7 @@ static void Draw(void) glColor3f(0,.9,0); glVertex3f(-0.9, 0.0, -30.0); - /* front-facing */ + /* CW / back-facing */ glColor3f(0,0,.7); glVertex3f( 0.1, -0.9, -30.0); glColor3f(.8,0,0); diff --git a/src/mesa/pipe/draw/draw_cull.c b/src/mesa/pipe/draw/draw_cull.c index 863686f150..e563f9f45f 100644 --- a/src/mesa/pipe/draw/draw_cull.c +++ b/src/mesa/pipe/draw/draw_cull.c @@ -40,7 +40,7 @@ struct cull_stage { struct draw_stage stage; - GLuint mode; /**< one of PIPE_WINDING_x */ + GLuint winding; /**< which winding(s) to cull (one of PIPE_WINDING_x) */ }; @@ -54,7 +54,7 @@ static void cull_begin( struct draw_stage *stage ) { struct cull_stage *cull = cull_stage(stage); - cull->mode = stage->draw->setup.cull_mode; + cull->winding = stage->draw->setup.cull_mode; stage->next->begin( stage->next ); } @@ -78,10 +78,12 @@ static void cull_tri( struct draw_stage *stage, header->det = ex * fy - ey * fx; if (header->det != 0) { - /* non-zero area */ - GLuint mode = (header->det > 0) ? PIPE_WINDING_CW : PIPE_WINDING_CCW; + /* if (det > 0 then Z points toward camera and triangle is + * counter-clockwise winding. + */ + GLuint winding = (header->det > 0) ? PIPE_WINDING_CCW : PIPE_WINDING_CW; - if ((mode & cull_stage(stage)->mode) == 0) { + if ((winding & cull_stage(stage)->winding) == 0) { /* triangle is not culled, pass to next stage */ stage->next->tri( stage->next, header ); } diff --git a/src/mesa/pipe/draw/draw_twoside.c b/src/mesa/pipe/draw/draw_twoside.c index e86123e84d..9f26335fb6 100644 --- a/src/mesa/pipe/draw/draw_twoside.c +++ b/src/mesa/pipe/draw/draw_twoside.c @@ -35,8 +35,7 @@ struct twoside_stage { struct draw_stage stage; - - GLfloat facing; + GLfloat sign; /**< +1 or -1 */ const GLuint *lookup; }; @@ -51,7 +50,12 @@ static void twoside_begin( struct draw_stage *stage ) { struct twoside_stage *twoside = twoside_stage(stage); - twoside->facing = (stage->draw->setup.front_winding == PIPE_WINDING_CW) ? 1 : -1; + /* + * We'll multiply the primitive's determinant by this sign to determine + * if the triangle is back-facing (negative). + * sign = 1 for CCW, -1 for CW + */ + twoside->sign = (stage->draw->setup.front_winding == PIPE_WINDING_CCW) ? 1 : -1; stage->next->begin( stage->next ); } @@ -94,7 +98,7 @@ static void twoside_tri( struct draw_stage *stage, { struct twoside_stage *twoside = twoside_stage(stage); - if (header->det * twoside->facing < 0) { + if (header->det * twoside->sign < 0.0) { /* this is a back-facing triangle */ struct prim_header tmp; diff --git a/src/mesa/state_tracker/st_atom_setup.c b/src/mesa/state_tracker/st_atom_setup.c index 8b95ea958e..6ee96f6178 100644 --- a/src/mesa/state_tracker/st_atom_setup.c +++ b/src/mesa/state_tracker/st_atom_setup.c @@ -78,13 +78,19 @@ static void update_setup_state( struct st_context *st ) /* _NEW_POLYGON, _NEW_BUFFERS */ { - setup.front_winding = PIPE_WINDING_CW; - + if (ctx->Polygon.FrontFace == GL_CCW) + setup.front_winding = PIPE_WINDING_CCW; + else + setup.front_winding = PIPE_WINDING_CW; + + /* XXX + * I think the intention here is that user-created framebuffer objects + * use Y=0=TOP layout instead of OpenGL's normal Y=0=bottom layout. + * Flipping Y changes CW to CCW and vice-versa. + * But this is an implementation/driver-specific artifact - remove... + */ if (ctx->DrawBuffer && ctx->DrawBuffer->Name != 0) - setup.front_winding ^= PIPE_WINDING_BOTH; - - if (ctx->Polygon.FrontFace != GL_CCW) - setup.front_winding ^= PIPE_WINDING_BOTH; + setup.front_winding ^= PIPE_WINDING_BOTH; } /* _NEW_LIGHT @@ -92,14 +98,18 @@ static void update_setup_state( struct st_context *st ) if (ctx->Light.ShadeModel == GL_FLAT) setup.flatshade = 1; - /* _NEW_LIGHT + /* _NEW_LIGHT | _NEW_PROGRAM * - * Not sure about the light->enabled requirement - does this still - * apply?? + * Back-face colors can come from traditional lighting (when + * GL_LIGHT_MODEL_TWO_SIDE is set) or from vertex programs (when + * GL_VERTEX_PROGRAM_TWO_SIDE is set). Note the logic here. */ - if (ctx->Light.Enabled && - ctx->Light.Model.TwoSide) + if (ctx->VertexProgram._Enabled) { + setup.light_twoside = ctx->VertexProgram.TwoSideEnabled; + } + else if (ctx->Light.Enabled && ctx->Light.Model.TwoSide) { setup.light_twoside = 1; + } /* _NEW_POLYGON */ |