/************************************************************************** * * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas. * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sub license, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice (including the * next paragraph) shall be included in all copies or substantial portions * of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * **************************************************************************/ /** * Triangle rendering within a tile. */ #include "pipe/p_compiler.h" #include "pipe/p_format.h" #include "pipe/p_util.h" #include "spu_main.h" #include "spu_tile.h" #include "spu_tri.h" /** * Simplified types taken from other parts of Gallium */ struct vertex_header { float data[2][4]; /* pos and color */ }; struct prim_header { struct vertex_header *v[3]; }; /* XXX fix this */ #undef CEILF #define CEILF(X) ((float) (int) ((X) + 0.99999)) #define QUAD_TOP_LEFT 0 #define QUAD_TOP_RIGHT 1 #define QUAD_BOTTOM_LEFT 2 #define QUAD_BOTTOM_RIGHT 3 #define MASK_TOP_LEFT (1 << QUAD_TOP_LEFT) #define MASK_TOP_RIGHT (1 << QUAD_TOP_RIGHT) #define MASK_BOTTOM_LEFT (1 << QUAD_BOTTOM_LEFT) #define MASK_BOTTOM_RIGHT (1 << QUAD_BOTTOM_RIGHT) #define MASK_ALL 0xf #define DEBUG_VERTS 0 /** * Triangle edge info */ struct edge { float dx; /**< X(v1) - X(v0), used only during setup */ float dy; /**< Y(v1) - Y(v0), used only during setup */ float dxdy; /**< dx/dy */ float sx, sy; /**< first sample point coord */ int lines; /**< number of lines on this edge */ }; struct interp_coef { float a0[4]; float dadx[4]; float dady[4]; }; /** * Triangle setup info (derived from draw_stage). * Also used for line drawing (taking some liberties). */ struct setup_stage { /* Vertices are just an array of floats making up each attribute in * turn. Currently fixed at 4 floats, but should change in time. * Codegen will help cope with this. */ const struct vertex_header *vmax; const struct vertex_header *vmid; const struct vertex_header *vmin; const struct vertex_header *vprovoke; struct edge ebot; struct edge etop; struct edge emaj; float oneoverarea; uint tx, ty; int cliprect_minx, cliprect_maxx, cliprect_miny, cliprect_maxy; #if 0 struct tgsi_interp_coef coef[PIPE_MAX_SHADER_INPUTS]; #else struct interp_coef coef[PIPE_MAX_SHADER_INPUTS]; #endif #if 0 struct quad_header quad; #endif struct { int left[2]; /**< [0] = row0, [1] = row1 */ int right[2]; int y; unsigned y_flags; unsigned mask; /**< mask of MASK_BOTTOM/TOP_LEFT/RIGHT bits */ } span; }; #if 0 /** * Basically a cast wrapper. */ static INLINE struct setup_stage *setup_stage( struct draw_stage *stage ) { return (struct setup_stage *)stage; } #endif #if 0 /** * Clip setup->quad against the scissor/surface bounds. */ static INLINE void quad_clip(struct setup_stage *setup) { const struct pipe_scissor_state *cliprect = &setup->softpipe->cliprect; const int minx = (int) cliprect->minx; const int maxx = (int) cliprect->maxx; const int miny = (int) cliprect->miny; const int maxy = (int) cliprect->maxy; if (setup->quad.x0 >= maxx || setup->quad.y0 >= maxy || setup->quad.x0 + 1 < minx || setup->quad.y0 + 1 < miny) { /* totally clipped */ setup->quad.mask = 0x0; return; } if (setup->quad.x0 < minx) setup->quad.mask &= (MASK_BOTTOM_RIGHT | MASK_TOP_RIGHT); if (setup->quad.y0 < miny) setup->quad.mask &= (MASK_BOTTOM_LEFT | MASK_BOTTOM_RIGHT); if (setup->quad.x0 == maxx - 1) setup->quad.mask &= (MASK_BOTTOM_LEFT | MASK_TOP_LEFT); if (setup->quad.y0 == maxy - 1) setup->quad.mask &= (MASK_TOP_LEFT | MASK_TOP_RIGHT); } #endif #if 0 /** * Emit a quad (pass to next stage) with clipping. */ static INLINE void clip_emit_quad(struct setup_stage *setup) { quad_clip(setup); if (setup->quad.mask) { struct softpipe_context *sp = setup->softpipe; sp->quad.first->run(sp->quad.first, &setup->quad); } } #endif /** * Evaluate attribute coefficients (plane equations) to compute * attribute values for the four fragments in a quad. * Eg: four colors will be compute. */ static INLINE void eval_coeff( struct setup_stage *setup, uint slot, float x, float y, float result[4][4]) { uint i; const float *dadx = setup->coef[slot].dadx; const float *dady = setup->coef[slot].dady; /* loop over XYZW comps */ for (i = 0; i < 4; i++) { result[QUAD_TOP_LEFT][i] = setup->coef[slot].a0[i] + x * dadx[i] + y * dady[i]; result[QUAD_TOP_RIGHT][i] = result[0][i] + dadx[i]; result[QUAD_BOTTOM_LEFT][i] = result[0][i] + dady[i]; result[QUAD_BOTTOM_RIGHT][i] = result[0][i] + dadx[i] + dady[i]; } } static INLINE void eval_z( struct setup_stage *setup, float x, float y, float result[4]) { const uint slot = 0; const uint i = 2; const float *dadx = setup->coef[slot].dadx; const float *dady = setup->coef[slot].dady; result[QUAD_TOP_LEFT] = setup->coef[slot].a0[i] + x * dadx[i] + y * dady[i]; result[QUAD_TOP_RIGHT] = result[0] + dadx[i]; result[QUAD_BOTTOM_LEFT] = result[0] + dady[i]; result[QUAD_BOTTOM_RIGHT] = result[0] + dadx[i] + dady[i]; } static INLINE uint pack_color(const float color[4]) { uint r = (uint) (color[0] * 255.0); uint g = (uint) (color[1] * 255.0); uint b = (uint) (color[2] * 255.0); uint a = (uint) (color[3] * 255.0); r = MIN2(r, 255); g = MIN2(g, 255); b = MIN2(b, 255); a = MIN2(a, 255); switch (spu.fb.color_format) { case PIPE_FORMAT_A8R8G8B8_UNORM: return (a << 24) | (r << 16) | (g << 8) | b; case PIPE_FORMAT_B8G8R8A8_UNORM: return (b << 24) | (g << 16) | (r << 8) | a; default: ASSERT(0); return 0; } } static uint do_depth_test(struct setup_stage *setup, int x, int y, unsigned mask) { int ix = x - setup->cliprect_minx; int iy = y - setup->cliprect_miny; float zvals[4]; eval_z(setup, (float) x, (float) y, zvals); if (tile_status_z[setup->ty][setup->tx] == TILE_STATUS_CLEAR) { /* now, _really_ clear the tile */ clear_z_tile(&ztile); } else { /* make sure we've got the tile from main mem */ wait_on_mask(1 << TAG_READ_TILE_Z); } tile_status_z[setup->ty][setup->tx] = TILE_STATUS_DIRTY; if (spu.fb.depth_format == PIPE_FORMAT_Z16_UNORM) { const float zscale = 65535.0; if (mask & MASK_TOP_LEFT) { uint z = (uint) (zvals[0] * zscale); if (z < ztile.t16[iy][ix]) ztile.t16[iy][ix] = z; else mask &= ~MASK_TOP_LEFT; } if (mask & MASK_TOP_RIGHT) { uint z = (uint) (zvals[1] * zscale); if (z < ztile.t16[iy][ix+1]) ztile.t16[iy][ix+1] = z; else mask &= ~MASK_TOP_RIGHT; } if (mask & MASK_BOTTOM_LEFT) { uint z = (uint) (zvals[2] * zscale); if (z < ztile.t16[iy+1][ix]) ztile.t16[iy+1][ix] = z; else mask &= ~MASK_BOTTOM_LEFT; } if (mask & MASK_BOTTOM_RIGHT) { uint z = (uint) (zvals[3] * zscale); if (z < ztile.t16[iy+1][ix+1]) ztile.t16[iy+1][ix+1] = z; else mask &= ~MASK_BOTTOM_RIGHT; } } else { const float zscale = (float) 0xffffffff; ASSERT(spu.fb.depth_format == PIPE_FORMAT_Z32_UNORM); if (mask & MASK_TOP_LEFT) { uint z = (uint) (zvals[0] * zscale); if (z < ztile.t32[iy][ix]) ztile.t32[iy][ix] = z; else mask &= ~MASK_TOP_LEFT; } if (mask & MASK_TOP_RIGHT) { uint z = (uint) (zvals[1] * zscale); if (z < ztile.t32[iy][ix+1]) ztile.t32[iy][ix+1] = z; else mask &= ~MASK_TOP_RIGHT; } if (mask & MASK_BOTTOM_LEFT) { uint z = (uint) (zvals[2] * zscale); if (z < ztile.t32[iy+1][ix]) ztile.t32[iy+1][ix] = z; else mask &= ~MASK_BOTTOM_LEFT; } if (mask & MASK_BOTTOM_RIGHT) { uint z = (uint) (zvals[3] * zscale); if (z < ztile.t32[iy+1][ix+1]) ztile.t32[iy+1][ix+1] = z; else mask &= ~MASK_BOTTOM_RIGHT; } } return mask; } /** * Emit a quad (pass to next stage). No clipping is done. */ static INLINE void emit_quad( struct setup_stage *setup, int x, int y, unsigned mask ) { #if 0 struct softpipe_context *sp = setup->softpipe; setup->quad.x0 = x; setup->quad.y0 = y; setup->quad.mask = mask; sp->quad.first->run(sp->quad.first, &setup->quad); #else /* Cell: "write" quad fragments to the tile by setting prim color */ const int ix = x - setup->cliprect_minx; const int iy = y - setup->cliprect_miny; float colors[4][4]; eval_coeff(setup, 1, (float) x, (float) y, colors); if (spu.depth_stencil.depth.enabled) { mask &= do_depth_test(setup, x, y, mask); } if (mask) { if (tile_status[setup->ty][setup->tx] == TILE_STATUS_CLEAR) { /* now, _really_ clear the tile */ clear_c_tile(ctile); } else { /* make sure we've got the tile from main mem */ wait_on_mask(1 << TAG_READ_TILE_COLOR); } tile_status[setup->ty][setup->tx] = TILE_STATUS_DIRTY; if (mask & MASK_TOP_LEFT) ctile[iy][ix] = pack_color(colors[QUAD_TOP_LEFT]); if (mask & MASK_TOP_RIGHT) ctile[iy][ix+1] = pack_color(colors[QUAD_TOP_RIGHT]); if (mask & MASK_BOTTOM_LEFT) ctile[iy+1][ix] = pack_color(colors[QUAD_BOTTOM_LEFT]); if (mask & MASK_BOTTOM_RIGHT) ctile[iy+1][ix+1] = pack_color(colors[QUAD_BOTTOM_RIGHT]); } #endif } /** * Given an X or Y coordinate, return the block/quad coordinate that it * belongs to. */ static INLINE int block( int x ) { return x & ~1; } /** * Compute mask which indicates which pixels in the 2x2 quad are actually inside * the triangle's bounds. * * this is pretty nasty... may need to rework flush_spans again to * fix it, if possible. */ static unsigned calculate_mask( struct setup_stage *setup, int x ) { unsigned mask = 0x0; if (x >= setup->span.left[0] && x < setup->span.right[0]) mask |= MASK_TOP_LEFT; if (x >= setup->span.left[1] && x < setup->span.right[1]) mask |= MASK_BOTTOM_LEFT; if (x+1 >= setup->span.left[0] && x+1 < setup->span.right[0]) mask |= MASK_TOP_RIGHT; if (x+1 >= setup->span.left[1] && x+1 < setup->span.right[1]) mask |= MASK_BOTTOM_RIGHT; return mask; } /** * Render a horizontal span of quads */ static void flush_spans( struct setup_stage *setup ) { int minleft, maxright; int x; switch (setup->span.y_flags) { case 0x3: /* both odd and even lines written (both quad rows) */ minleft = MIN2(setup->span.left[0], setup->span.left[1]); maxright = MAX2(setup->span.right[0], setup->span.right[1]); break; case 0x1: /* only even line written (quad top row) */ minleft = setup->span.left[0]; maxright = setup->span.right[0]; break; case 0x2: /* only odd line written (quad bottom row) */ minleft = setup->span.left[1]; maxright = setup->span.right[1]; break; default: return; } /* XXX this loop could be moved into the above switch cases and * calculate_mask() could be simplified a bit... */ for (x = block(minleft); x <= block(maxright); x += 2) { emit_quad( setup, x, setup->span.y, calculate_mask( setup, x ) ); } setup->span.y = 0; setup->span.y_flags = 0; setup->span.right[0] = 0; setup->span.right[1] = 0; } #if DEBUG_VERTS static void print_vertex(const struct setup_stage *setup, const struct vertex_header *v) { int i; fprintf(stderr, "Vertex: (%p)\n", v); for (i = 0; i < setup->quad.nr_attrs; i++) { fprintf(stderr, " %d: %f %f %f %f\n", i, v->data[i][0], v->data[i][1], v->data[i][2], v->data[i][3]); } } #endif static boolean setup_sort_vertices( struct setup_stage *setup, const struct prim_header *prim ) { const struct vertex_header *v0 = prim->v[0]; const struct vertex_header *v1 = prim->v[1]; const struct vertex_header *v2 = prim->v[2]; #if DEBUG_VERTS fprintf(stderr, "Triangle:\n"); print_vertex(setup, v0); print_vertex(setup, v1); print_vertex(setup, v2); #endif setup->vprovoke = v2; /* determine bottom to top order of vertices */ { float y0 = v0->data[0][1]; float y1 = v1->data[0][1]; float y2 = v2->data[0][1]; if (y0 <= y1) { if (y1 <= y2) { /* y0<=y1<=y2 */ setup->vmin = v0; setup->vmid = v1; setup->vmax = v2; } else if (y2 <= y0) { /* y2<=y0<=y1 */ setup->vmin = v2; setup->vmid = v0; setup->vmax = v1; } else { /* y0<=y2<=y1 */ setup->vmin = v0; setup->vmid = v2; setup->vmax = v1; } } else { if (y0 <= y2) { /* y1<=y0<=y2 */ setup->vmin = v1; setup->vmid = v0; setup->vmax = v2; } else if (y2 <= y1) { /* y2<=y1<=y0 */ setup->vmin = v2; setup->vmid = v1; setup->vmax = v0; } else { /* y1<=y2<=y0 */ setup->vmin = v1; setup->vmid = v2; setup->vmax = v0; } } } /* Check if triangle is completely outside the tile bounds */ if (setup->vmin->data[0][1] > setup->cliprect_maxy) return FALSE; if (setup->vmax->data[0][1] < setup->cliprect_miny) return FALSE; if (setup->vmin->data[0][0] < setup->cliprect_minx && setup->vmid->data[0][0] < setup->cliprect_minx && setup->vmax->data[0][0] < setup->cliprect_minx) return FALSE; if (setup->vmin->data[0][0] > setup->cliprect_maxx && setup->vmid->data[0][0] > setup->cliprect_maxx && setup->vmax->data[0][0] > setup->cliprect_maxx) return FALSE; setup->ebot.dx = setup->vmid->data[0][0] - setup->vmin->data[0][0]; setup->ebot.dy = setup->vmid->data[0][1] - setup->vmin->data[0][1]; setup->emaj.dx = setup->vmax->data[0][0] - setup->vmin->data[0][0]; setup->emaj.dy = setup->vmax->data[0][1] - setup->vmin->data[0][1]; setup->etop.dx = setup->vmax->data[0][0] - setup->vmid->data[0][0]; setup->etop.dy = setup->vmax->data[0][1] - setup->vmid->data[0][1]; /* * Compute triangle's area. Use 1/area to compute partial * derivatives of attributes later. * * The area will be the same as prim->det, but the sign may be * different depending on how the vertices get sorted above. * * To determine whether the primitive is front or back facing we * use the prim->det value because its sign is correct. */ { const float area = (setup->emaj.dx * setup->ebot.dy - setup->ebot.dx * setup->emaj.dy); setup->oneoverarea = 1.0f / area; /* _mesa_printf("%s one-over-area %f area %f det %f\n", __FUNCTION__, setup->oneoverarea, area, prim->det ); */ } #if 0 /* We need to know if this is a front or back-facing triangle for: * - the GLSL gl_FrontFacing fragment attribute (bool) * - two-sided stencil test */ setup->quad.facing = (prim->det > 0.0) ^ (setup->softpipe->rasterizer->front_winding == PIPE_WINDING_CW); #endif return TRUE; } #if 0 /** * Compute a0 for a constant-valued coefficient (GL_FLAT shading). * The value value comes from vertex->data[slot][i]. * The result will be put into setup->coef[slot].a0[i]. * \param slot which attribute slot * \param i which component of the slot (0..3) */ static void const_coeff( struct setup_stage *setup, unsigned slot, unsigned i ) { assert(slot < PIPE_MAX_SHADER_INPUTS); assert(i <= 3); setup->coef[slot].dadx[i] = 0; setup->coef[slot].dady[i] = 0; /* need provoking vertex info! */ setup->coef[slot].a0[i] = setup->vprovoke->data[slot][i]; } #endif /** * Compute a0, dadx and dady for a linearly interpolated coefficient, * for a triangle. */ static void tri_linear_coeff( struct setup_stage *setup, uint slot, uint firstComp, uint lastComp ) { uint i; for (i = firstComp; i < lastComp; i++) { float botda = setup->vmid->data[slot][i] - setup->vmin->data[slot][i]; float majda = setup->vmax->data[slot][i] - setup->vmin->data[slot][i]; float a = setup->ebot.dy * majda - botda * setup->emaj.dy; float b = setup->emaj.dx * botda - majda * setup->ebot.dx; ASSERT(slot < PIPE_MAX_SHADER_INPUTS); setup->coef[slot].dadx[i] = a * setup->oneoverarea; setup->coef[slot].dady[i] = b * setup->oneoverarea; /* calculate a0 as the value which would be sampled for the * fragment at (0,0), taking into account that we want to sample at * pixel centers, in other words (0.5, 0.5). * * this is neat but unfortunately not a good way to do things for * triangles with very large values of dadx or dady as it will * result in the subtraction and re-addition from a0 of a very * large number, which means we'll end up loosing a lot of the * fractional bits and precision from a0. the way to fix this is * to define a0 as the sample at a pixel center somewhere near vmin * instead - i'll switch to this later. */ setup->coef[slot].a0[i] = (setup->vmin->data[slot][i] - (setup->coef[slot].dadx[i] * (setup->vmin->data[0][0] - 0.5f) + setup->coef[slot].dady[i] * (setup->vmin->data[0][1] - 0.5f))); } /* _mesa_printf("attr[%d].%c: %f dx:%f dy:%f\n", slot, "xyzw"[i], setup->coef[slot].a0[i], setup->coef[slot].dadx[i], setup->coef[slot].dady[i]); */ } #if 0 /** * Compute a0, dadx and dady for a perspective-corrected interpolant, * for a triangle. * We basically multiply the vertex value by 1/w before computing * the plane coefficients (a0, dadx, dady). * Later, when we compute the value at a particular fragment position we'll * divide the interpolated value by the interpolated W at that fragment. */ static void tri_persp_coeff( struct setup_stage *setup, unsigned slot, unsigned i ) { /* premultiply by 1/w: */ float mina = setup->vmin->data[slot][i] * setup->vmin->data[0][3]; float mida = setup->vmid->data[slot][i] * setup->vmid->data[0][3]; float maxa = setup->vmax->data[slot][i] * setup->vmax->data[0][3]; float botda = mida - mina; float majda = maxa - mina; float a = setup->ebot.dy * majda - botda * setup->emaj.dy; float b = setup->emaj.dx * botda - majda * setup->ebot.dx; /* printf("tri persp %d,%d: %f %f %f\n", slot, i, setup->vmin->data[slot][i], setup->vmid->data[slot][i], setup->vmax->data[slot][i] ); */ assert(slot < PIPE_MAX_SHADER_INPUTS); assert(i <= 3); setup->coef[slot].dadx[i] = a * setup->oneoverarea; setup->coef[slot].dady[i] = b * setup->oneoverarea; setup->coef[slot].a0[i] = (mina - (setup->coef[slot].dadx[i] * (setup->vmin->data[0][0] - 0.5f) + setup->coef[slot].dady[i] * (setup->vmin->data[0][1] - 0.5f))); } #endif /** * Compute the setup->coef[] array dadx, dady, a0 values. * Must be called after setup->vmin,vmid,vmax,vprovoke are initialized. */ static void setup_tri_coefficients( struct setup_stage *setup ) { #if 0 const enum interp_mode *interp = setup->softpipe->vertex_info.interp_mode; unsigned slot, j; /* z and w are done by linear interpolation: */ tri_linear_coeff(setup, 0, 2); tri_linear_coeff(setup, 0, 3); /* setup interpolation for all the remaining attributes: */ for (slot = 1; slot < setup->quad.nr_attrs; slot++) { switch (interp[slot]) { case INTERP_CONSTANT: for (j = 0; j < NUM_CHANNELS; j++) const_coeff(setup, slot, j); break; case INTERP_LINEAR: for (j = 0; j < NUM_CHANNELS; j++) tri_linear_coeff(setup, slot, j); break; case INTERP_PERSPECTIVE: for (j = 0; j < NUM_CHANNELS; j++) tri_persp_coeff(setup, slot, j); break; default: /* invalid interp mode */ assert(0); } } #else tri_linear_coeff(setup, 0, 2, 3); /* slot 0, z */ tri_linear_coeff(setup, 1, 0, 4); /* slot 1, color */ #endif } static void setup_tri_edges( struct setup_stage *setup ) { float vmin_x = setup->vmin->data[0][0] + 0.5f; float vmid_x = setup->vmid->data[0][0] + 0.5f; float vmin_y = setup->vmin->data[0][1] - 0.5f; float vmid_y = setup->vmid->data[0][1] - 0.5f; float vmax_y = setup->vmax->data[0][1] - 0.5f; setup->emaj.sy = CEILF(vmin_y); setup->emaj.lines = (int) CEILF(vmax_y - setup->emaj.sy); setup->emaj.dxdy = setup->emaj.dx / setup->emaj.dy; setup->emaj.sx = vmin_x + (setup->emaj.sy - vmin_y) * setup->emaj.dxdy; setup->etop.sy = CEILF(vmid_y); setup->etop.lines = (int) CEILF(vmax_y - setup->etop.sy); setup->etop.dxdy = setup->etop.dx / setup->etop.dy; setup->etop.sx = vmid_x + (setup->etop.sy - vmid_y) * setup->etop.dxdy; setup->ebot.sy = CEILF(vmin_y); setup->ebot.lines = (int) CEILF(vmid_y - setup->ebot.sy); setup->ebot.dxdy = setup->ebot.dx / setup->ebot.dy; setup->ebot.sx = vmin_x + (setup->ebot.sy - vmin_y) * setup->ebot.dxdy; } /** * Render the upper or lower half of a triangle. * Scissoring/cliprect is applied here too. */ static void subtriangle( struct setup_stage *setup, struct edge *eleft, struct edge *eright, unsigned lines ) { const int minx = setup->cliprect_minx; const int maxx = setup->cliprect_maxx; const int miny = setup->cliprect_miny; const int maxy = setup->cliprect_maxy; int y, start_y, finish_y; int sy = (int)eleft->sy; ASSERT((int)eleft->sy == (int) eright->sy); /* clip top/bottom */ start_y = sy; finish_y = sy + lines; if (start_y < miny) start_y = miny; if (finish_y > maxy) finish_y = maxy; start_y -= sy; finish_y -= sy; /* _mesa_printf("%s %d %d\n", __FUNCTION__, start_y, finish_y); */ for (y = start_y; y < finish_y; y++) { /* avoid accumulating adds as floats don't have the precision to * accurately iterate large triangle edges that way. luckily we * can just multiply these days. * * this is all drowned out by the attribute interpolation anyway. */ int left = (int)(eleft->sx + y * eleft->dxdy); int right = (int)(eright->sx + y * eright->dxdy); /* clip left/right */ if (left < minx) left = minx; if (right > maxx) right = maxx; if (left < right) { int _y = sy + y; if (block(_y) != setup->span.y) { flush_spans(setup); setup->span.y = block(_y); } setup->span.left[_y&1] = left; setup->span.right[_y&1] = right; setup->span.y_flags |= 1<<(_y&1); } } /* save the values so that emaj can be restarted: */ eleft->sx += lines * eleft->dxdy; eright->sx += lines * eright->dxdy; eleft->sy += lines; eright->sy += lines; } /** * Do setup for triangle rasterization, then render the triangle. */ static void setup_tri(struct setup_stage *setup, struct prim_header *prim) { if (!setup_sort_vertices( setup, prim )) { return; /* totally clipped */ } setup_tri_coefficients( setup ); setup_tri_edges( setup ); #if 0 setup->quad.prim = PRIM_TRI; #endif setup->span.y = 0; setup->span.y_flags = 0; setup->span.right[0] = 0; setup->span.right[1] = 0; /* setup->span.z_mode = tri_z_mode( setup->ctx ); */ /* init_constant_attribs( setup ); */ if (setup->oneoverarea < 0.0) { /* emaj on left: */ subtriangle( setup, &setup->emaj, &setup->ebot, setup->ebot.lines ); subtriangle( setup, &setup->emaj, &setup->etop, setup->etop.lines ); } else { /* emaj on right: */ subtriangle( setup, &setup->ebot, &setup->emaj, setup->ebot.lines ); subtriangle( setup, &setup->etop, &setup->emaj, setup->etop.lines ); } flush_spans( setup ); } /** * Draw triangle into tile at (tx, ty) (tile coords) * The tile data should have already been fetched. */ void tri_draw(const float *v0, const float *v1, const float *v2, uint tx, uint ty) { struct prim_header tri; struct setup_stage setup; tri.v[0] = (struct vertex_header *) v0; tri.v[1] = (struct vertex_header *) v1; tri.v[2] = (struct vertex_header *) v2; setup.tx = tx; setup.ty = ty; /* set clipping bounds to tile bounds */ setup.cliprect_minx = tx * TILE_SIZE; setup.cliprect_miny = ty * TILE_SIZE; setup.cliprect_maxx = (tx + 1) * TILE_SIZE; setup.cliprect_maxy = (ty + 1) * TILE_SIZE; setup_tri(&setup, &tri); }