--- /dev/null
+/***************************************************************************
+* Copyright (C) 2010 PCSX4ALL Team *
+* Copyright (C) 2010 Unai *
+* Copyright (C) 2016 Senquack (dansilsby <AT> gmail <DOT> com) *
+* *
+* This program is free software; you can redistribute it and/or modify *
+* it under the terms of the GNU General Public License as published by *
+* the Free Software Foundation; either version 2 of the License, or *
+* (at your option) any later version. *
+* *
+* This program is distributed in the hope that it will be useful, *
+* but WITHOUT ANY WARRANTY; without even the implied warranty of *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
+* GNU General Public License for more details. *
+* *
+* You should have received a copy of the GNU General Public License *
+* along with this program; if not, write to the *
+* Free Software Foundation, Inc., *
+* 51 Franklin Street, Fifth Floor, Boston, MA 02111-1307 USA. *
+***************************************************************************/
+
+#ifndef __GPU_UNAI_GPU_RASTER_LINE_H__
+#define __GPU_UNAI_GPU_RASTER_LINE_H__
+
+///////////////////////////////////////////////////////////////////////////////
+// GPU internal line drawing functions
+//
+// Rewritten October 2016 by senquack:
+// Instead of one pixel at a time, lines are now drawn in runs of pixels,
+// whether vertical, horizontal, or diagonal. A new inner driver
+// 'gpuPixelSpanFn' is used, as well as an enhanced Bresenham run-slice
+// algorithm. For more information, see the following:
+//
+// Michael Abrash - Graphics Programming Black Book
+// Chapters 35 - 36 (does not implement diagonal runs)
+// http://www.drdobbs.com/parallel/graphics-programming-black-book/184404919
+// http://www.jagregory.com/abrash-black-book/
+//
+// Article by Andrew Delong (does not implement diagonal runs)
+// http://timetraces.ca/nw/drawline.htm
+//
+// 'Run-Based Multi-Point Line Drawing' by Eun Jae Lee & Larry F. Hodges
+// https://smartech.gatech.edu/bitstream/handle/1853/3632/93-22.pdf
+// Provided the idea of doing a half-octant transform allowing lines with
+// slopes between 0.5 and 2.0 (diagonal runs of pixels) to be handled
+// identically to the traditional horizontal/vertical run-slice method.
+
+// Use 16.16 fixed point precision for line math.
+// NOTE: Gouraud colors used by gpuPixelSpanFn can use a different precision.
+#define GPU_LINE_FIXED_BITS 16
+
+// If defined, Gouraud lines will use fixed-point multiply-by-inverse to
+// do most divisions. With enough accuracy, this should be OK.
+#define USE_LINES_ALL_FIXED_PT_MATH
+
+//////////////////////
+// Flat-shaded line //
+//////////////////////
+void gpuDrawLineF(PtrUnion packet, const PSD gpuPixelSpanDriver)
+{
+ int x0, y0, x1, y1;
+ int dx, dy;
+
+ // All three of these variables should be signed (so multiplication works)
+ ptrdiff_t sx; // Sign of x delta, positive when x0 < x1
+ const ptrdiff_t dst_depth = FRAME_BYTES_PER_PIXEL; // PSX: 2 bytes per pixel
+ const ptrdiff_t dst_stride = FRAME_BYTE_STRIDE; // PSX: 2048 bytes per framebuffer line
+
+ // Clip region: xmax/ymax seem to normally be one *past* the rightmost/
+ // bottommost pixels of the draw area. Since we render every pixel between
+ // and including both line endpoints, subtract one from xmax/ymax.
+ const int xmin = gpu_senquack.DrawingArea[0];
+ const int ymin = gpu_senquack.DrawingArea[1];
+ const int xmax = gpu_senquack.DrawingArea[2] - 1;
+ const int ymax = gpu_senquack.DrawingArea[3] - 1;
+
+ x0 = GPU_EXPANDSIGN(packet.S2[2]) + gpu_senquack.DrawingOffset[0];
+ y0 = GPU_EXPANDSIGN(packet.S2[3]) + gpu_senquack.DrawingOffset[1];
+ x1 = GPU_EXPANDSIGN(packet.S2[4]) + gpu_senquack.DrawingOffset[0];
+ y1 = GPU_EXPANDSIGN(packet.S2[5]) + gpu_senquack.DrawingOffset[1];
+
+ // Always draw top to bottom, so ensure y0 <= y1
+ if (y0 > y1) {
+ SwapValues(y0, y1);
+ SwapValues(x0, x1);
+ }
+
+ // Is line totally outside Y clipping range?
+ if (y0 > ymax || y1 < ymin) return;
+
+ dx = x1 - x0;
+ dy = y1 - y0;
+
+ // X-axis range check : max distance between any two X coords is 1023
+ // (PSX hardware will not render anything violating this rule)
+ // NOTE: We'll check y coord range further below
+ if (dx >= CHKMAX_X || dx <= -CHKMAX_X)
+ return;
+
+ // Y-axis range check and clipping
+ if (dy) {
+ // Y-axis range check : max distance between any two Y coords is 511
+ // (PSX hardware will not render anything violating this rule)
+ if (dy >= CHKMAX_Y)
+ return;
+
+ // We already know y0 < y1
+ if (y0 < ymin) {
+ x0 += GPU_FAST_DIV(((ymin - y0) * dx), dy);
+ y0 = ymin;
+ }
+ if (y1 > ymax) {
+ x1 += GPU_FAST_DIV(((ymax - y1) * dx), dy);
+ y1 = ymax;
+ }
+
+ // Recompute in case clipping occurred:
+ dx = x1 - x0;
+ dy = y1 - y0;
+ }
+
+ // Check X clipping range, set 'sx' x-direction variable
+ if (dx == 0) {
+ // Is vertical line totally outside X clipping range?
+ if (x0 < xmin || x0 > xmax)
+ return;
+ sx = 0;
+ } else {
+ if (dx > 0) {
+ // x0 is leftmost coordinate
+ if (x0 > xmax) return; // Both points outside X clip range
+
+ if (x0 < xmin) {
+ if (x1 < xmin) return; // Both points outside X clip range
+ y0 += GPU_FAST_DIV(((xmin - x0) * dy), dx);
+ x0 = xmin;
+ }
+
+ if (x1 > xmax) {
+ y1 += GPU_FAST_DIV(((xmax - x1) * dy), dx);
+ x1 = xmax;
+ }
+
+ sx = +1;
+ dx = x1 - x0; // Get final value, which should also be absolute value
+ } else {
+ // x1 is leftmost coordinate
+ if (x1 > xmax) return; // Both points outside X clip range
+
+ if (x1 < xmin) {
+ if (x0 < xmin) return; // Both points outside X clip range
+
+ y1 += GPU_FAST_DIV(((xmin - x1) * dy), dx);
+ x1 = xmin;
+ }
+
+ if (x0 > xmax) {
+ y0 += GPU_FAST_DIV(((xmax - x0) * dy), dx);
+ x0 = xmax;
+ }
+
+ sx = -1;
+ dx = x0 - x1; // Get final value, which should also be absolute value
+ }
+
+ // Recompute in case clipping occurred:
+ dy = y1 - y0;
+ }
+
+ // IMPORTANT: dx,dy should now contain their absolute values
+
+ int min_length, // Minimum length of a pixel run
+ start_length, // Length of first run
+ end_length, // Length of last run
+ err_term, // Cumulative error to determine when to draw longer run
+ err_adjup, // Increment to err_term for each run drawn
+ err_adjdown; // Subract this from err_term after drawing longer run
+
+ // Color to draw with (16 bits, highest of which is unset mask bit)
+ uintptr_t col16 = GPU_RGB16(packet.U4[0]);
+
+ // We use u8 pointers even though PS1 has u16 framebuffer.
+ // This allows pixel-drawing functions to increment dst pointer
+ // directly by the passed 'incr' value, not having to shift it first.
+ u8 *dst = (u8*)gpu_senquack.vram + y0 * dst_stride + x0 * dst_depth;
+
+ // SPECIAL CASE: Vertical line
+ if (dx == 0) {
+ gpuPixelSpanDriver(dst, col16, dst_stride, dy+1);
+ return;
+ }
+
+ // SPECIAL CASE: Horizontal line
+ if (dy == 0) {
+ gpuPixelSpanDriver(dst, col16, sx * dst_depth, dx+1);
+ return;
+ }
+
+ // SPECIAL CASE: Diagonal line
+ if (dx == dy) {
+ gpuPixelSpanDriver(dst, col16, dst_stride + (sx * dst_depth), dy+1);
+ return;
+ }
+
+ int major, minor; // Major axis, minor axis
+ ptrdiff_t incr_major, incr_minor; // Ptr increment for each step along axis
+
+ if (dx > dy) {
+ major = dx;
+ minor = dy;
+ } else {
+ major = dy;
+ minor = dx;
+ }
+
+ // Determine if diagonal or horizontal runs
+ if (major < (2 * minor)) {
+ // Diagonal runs, so perform half-octant transformation
+ minor = major - minor;
+
+ // Advance diagonally when drawing runs
+ incr_major = dst_stride + (sx * dst_depth);
+
+ // After drawing each run, correct for over-advance along minor axis
+ if (dx > dy)
+ incr_minor = -dst_stride;
+ else
+ incr_minor = -sx * dst_depth;
+ } else {
+ // Horizontal or vertical runs
+ if (dx > dy) {
+ incr_major = sx * dst_depth;
+ incr_minor = dst_stride;
+ } else {
+ incr_major = dst_stride;
+ incr_minor = sx * dst_depth;
+ }
+ }
+
+ if (minor > 1) {
+ // Minimum number of pixels each run
+ min_length = major / minor;
+
+ // Initial error term; reflects an initial step of 0.5 along minor axis
+ err_term = (major % minor) - (minor * 2);
+
+ // Increment err_term this much each step along minor axis; when
+ // err_term crosses zero, draw longer pixel run.
+ err_adjup = (major % minor) * 2;
+ } else {
+ min_length = major;
+ err_term = 0;
+ err_adjup = 0;
+ }
+
+ // Error term adjustment when err_term turns over; used to factor
+ // out the major-axis step made at that time
+ err_adjdown = minor * 2;
+
+ // The initial and last runs are partial, because minor axis advances
+ // only 0.5 for these runs, rather than 1. Each is half a full run,
+ // plus the initial pixel.
+ start_length = end_length = (min_length / 2) + 1;
+
+ if (min_length & 1) {
+ // If there're an odd number of pixels per run, we have 1 pixel that
+ // can't be allocated to either the initial or last partial run, so
+ // we'll add 0.5 to err_term so that this pixel will be handled
+ // by the normal full-run loop
+ err_term += minor;
+ } else {
+ // If the minimum run length is even and there's no fractional advance,
+ // we have one pixel that could go to either the initial or last
+ // partial run, which we arbitrarily allocate to the last run
+ if (err_adjup == 0)
+ start_length--; // Leave out the extra pixel at the start
+ }
+
+ // First run of pixels
+ dst = gpuPixelSpanDriver(dst, col16, incr_major, start_length);
+ dst += incr_minor;
+
+ // Middle runs of pixels
+ while (--minor > 0) {
+ int run_length = min_length;
+ err_term += err_adjup;
+
+ // If err_term passed 0, reset it and draw longer run
+ if (err_term > 0) {
+ err_term -= err_adjdown;
+ run_length++;
+ }
+
+ dst = gpuPixelSpanDriver(dst, col16, incr_major, run_length);
+ dst += incr_minor;
+ }
+
+ // Final run of pixels
+ gpuPixelSpanDriver(dst, col16, incr_major, end_length);
+}
+
+/////////////////////////
+// Gouraud-shaded line //
+/////////////////////////
+void gpuDrawLineG(PtrUnion packet, const PSD gpuPixelSpanDriver)
+{
+ int x0, y0, x1, y1;
+ int dx, dy, dr, dg, db;
+ u32 r0, g0, b0, r1, g1, b1;
+
+ // All three of these variables should be signed (so multiplication works)
+ ptrdiff_t sx; // Sign of x delta, positive when x0 < x1
+ const ptrdiff_t dst_depth = FRAME_BYTES_PER_PIXEL; // PSX: 2 bytes per pixel
+ const ptrdiff_t dst_stride = FRAME_BYTE_STRIDE; // PSX: 2048 bytes per framebuffer line
+
+ // Clip region: xmax/ymax seem to normally be one *past* the rightmost/
+ // bottommost pixels of the draw area. We'll render every pixel between
+ // and including both line endpoints, so subtract one from xmax/ymax.
+ const int xmin = gpu_senquack.DrawingArea[0];
+ const int ymin = gpu_senquack.DrawingArea[1];
+ const int xmax = gpu_senquack.DrawingArea[2] - 1;
+ const int ymax = gpu_senquack.DrawingArea[3] - 1;
+
+ x0 = GPU_EXPANDSIGN(packet.S2[2]) + gpu_senquack.DrawingOffset[0];
+ y0 = GPU_EXPANDSIGN(packet.S2[3]) + gpu_senquack.DrawingOffset[1];
+ x1 = GPU_EXPANDSIGN(packet.S2[6]) + gpu_senquack.DrawingOffset[0];
+ y1 = GPU_EXPANDSIGN(packet.S2[7]) + gpu_senquack.DrawingOffset[1];
+
+ u32 col0 = packet.U4[0];
+ u32 col1 = packet.U4[2];
+
+ // Always draw top to bottom, so ensure y0 <= y1
+ if (y0 > y1) {
+ SwapValues(y0, y1);
+ SwapValues(x0, x1);
+ SwapValues(col0, col1);
+ }
+
+ // Is line totally outside Y clipping range?
+ if (y0 > ymax || y1 < ymin) return;
+
+ // If defined, Gouraud colors are fixed-point 5.11, otherwise they are 8.16
+ // (This is only beneficial if using SIMD-optimized pixel driver)
+#ifdef GPU_GOURAUD_LOW_PRECISION
+ r0 = (col0 >> 3) & 0x1f; g0 = (col0 >> 11) & 0x1f; b0 = (col0 >> 19) & 0x1f;
+ r1 = (col1 >> 3) & 0x1f; g1 = (col1 >> 11) & 0x1f; b1 = (col1 >> 19) & 0x1f;
+#else
+ r0 = col0 & 0xff; g0 = (col0 >> 8) & 0xff; b0 = (col0 >> 16) & 0xff;
+ r1 = col1 & 0xff; g1 = (col1 >> 8) & 0xff; b1 = (col1 >> 16) & 0xff;
+#endif
+
+ dx = x1 - x0;
+ dy = y1 - y0;
+ dr = r1 - r0;
+ dg = g1 - g0;
+ db = b1 - b0;
+
+ // X-axis range check : max distance between any two X coords is 1023
+ // (PSX hardware will not render anything violating this rule)
+ // NOTE: We'll check y coord range further below
+ if (dx >= CHKMAX_X || dx <= -CHKMAX_X)
+ return;
+
+ // Y-axis range check and clipping
+ if (dy) {
+ // Y-axis range check : max distance between any two Y coords is 511
+ // (PSX hardware will not render anything violating this rule)
+ if (dy >= CHKMAX_Y)
+ return;
+
+ // We already know y0 < y1
+ if (y0 < ymin) {
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ s32 factor = GPU_FAST_DIV(((ymin - y0) << GPU_LINE_FIXED_BITS), dy);
+ x0 += (dx * factor) >> GPU_LINE_FIXED_BITS;
+ r0 += (dr * factor) >> GPU_LINE_FIXED_BITS;
+ g0 += (dg * factor) >> GPU_LINE_FIXED_BITS;
+ b0 += (db * factor) >> GPU_LINE_FIXED_BITS;
+#else
+ x0 += (ymin - y0) * dx / dy;
+ r0 += (ymin - y0) * dr / dy;
+ g0 += (ymin - y0) * dg / dy;
+ b0 += (ymin - y0) * db / dy;
+#endif
+ y0 = ymin;
+ }
+
+ if (y1 > ymax) {
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ s32 factor = GPU_FAST_DIV(((ymax - y1) << GPU_LINE_FIXED_BITS), dy);
+ x1 += (dx * factor) >> GPU_LINE_FIXED_BITS;
+ r1 += (dr * factor) >> GPU_LINE_FIXED_BITS;
+ g1 += (dg * factor) >> GPU_LINE_FIXED_BITS;
+ b1 += (db * factor) >> GPU_LINE_FIXED_BITS;
+#else
+ x1 += (ymax - y1) * dx / dy;
+ r1 += (ymax - y1) * dr / dy;
+ g1 += (ymax - y1) * dg / dy;
+ b1 += (ymax - y1) * db / dy;
+#endif
+ y1 = ymax;
+ }
+
+ // Recompute in case clipping occurred:
+ dx = x1 - x0;
+ dy = y1 - y0;
+ dr = r1 - r0;
+ dg = g1 - g0;
+ db = b1 - b0;
+ }
+
+ // Check X clipping range, set 'sx' x-direction variable
+ if (dx == 0) {
+ // Is vertical line totally outside X clipping range?
+ if (x0 < xmin || x0 > xmax)
+ return;
+ sx = 0;
+ } else {
+ if (dx > 0) {
+ // x0 is leftmost coordinate
+ if (x0 > xmax) return; // Both points outside X clip range
+
+ if (x0 < xmin) {
+ if (x1 < xmin) return; // Both points outside X clip range
+
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ s32 factor = GPU_FAST_DIV(((xmin - x0) << GPU_LINE_FIXED_BITS), dx);
+ y0 += (dy * factor) >> GPU_LINE_FIXED_BITS;
+ r0 += (dr * factor) >> GPU_LINE_FIXED_BITS;
+ g0 += (dg * factor) >> GPU_LINE_FIXED_BITS;
+ b0 += (db * factor) >> GPU_LINE_FIXED_BITS;
+#else
+ y0 += (xmin - x0) * dy / dx;
+ r0 += (xmin - x0) * dr / dx;
+ g0 += (xmin - x0) * dg / dx;
+ b0 += (xmin - x0) * db / dx;
+#endif
+ x0 = xmin;
+ }
+
+ if (x1 > xmax) {
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ s32 factor = GPU_FAST_DIV(((xmax - x1) << GPU_LINE_FIXED_BITS), dx);
+ y1 += (dy * factor) >> GPU_LINE_FIXED_BITS;
+ r1 += (dr * factor) >> GPU_LINE_FIXED_BITS;
+ g1 += (dg * factor) >> GPU_LINE_FIXED_BITS;
+ b1 += (db * factor) >> GPU_LINE_FIXED_BITS;
+#else
+ y1 += (xmax - x1) * dy / dx;
+ r1 += (xmax - x1) * dr / dx;
+ g1 += (xmax - x1) * dg / dx;
+ b1 += (xmax - x1) * db / dx;
+#endif
+ x1 = xmax;
+ }
+
+ sx = +1;
+ dx = x1 - x0; // Get final value, which should also be absolute value
+ } else {
+ // x1 is leftmost coordinate
+ if (x1 > xmax) return; // Both points outside X clip range
+
+ if (x1 < xmin) {
+ if (x0 < xmin) return; // Both points outside X clip range
+
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ s32 factor = GPU_FAST_DIV(((xmin - x1) << GPU_LINE_FIXED_BITS), dx);
+ y1 += (dy * factor) >> GPU_LINE_FIXED_BITS;
+ r1 += (dr * factor) >> GPU_LINE_FIXED_BITS;
+ g1 += (dg * factor) >> GPU_LINE_FIXED_BITS;
+ b1 += (db * factor) >> GPU_LINE_FIXED_BITS;
+#else
+ y1 += (xmin - x1) * dy / dx;
+ r1 += (xmin - x1) * dr / dx;
+ g1 += (xmin - x1) * dg / dx;
+ b1 += (xmin - x1) * db / dx;
+#endif
+ x1 = xmin;
+ }
+
+ if (x0 > xmax) {
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ s32 factor = GPU_FAST_DIV(((xmax - x0) << GPU_LINE_FIXED_BITS), dx);
+ y0 += (dy * factor) >> GPU_LINE_FIXED_BITS;
+ r0 += (dr * factor) >> GPU_LINE_FIXED_BITS;
+ g0 += (dg * factor) >> GPU_LINE_FIXED_BITS;
+ b0 += (db * factor) >> GPU_LINE_FIXED_BITS;
+#else
+ y0 += (xmax - x0) * dy / dx;
+ r0 += (xmax - x0) * dr / dx;
+ g0 += (xmax - x0) * dg / dx;
+ b0 += (xmax - x0) * db / dx;
+#endif
+ x0 = xmax;
+ }
+
+ sx = -1;
+ dx = x0 - x1; // Get final value, which should also be absolute value
+ }
+
+ // Recompute in case clipping occurred:
+ dy = y1 - y0;
+ dr = r1 - r0;
+ dg = g1 - g0;
+ db = b1 - b0;
+ }
+
+ // IMPORTANT: dx,dy should now contain their absolute values
+
+ int min_length, // Minimum length of a pixel run
+ start_length, // Length of first run
+ end_length, // Length of last run
+ err_term, // Cumulative error to determine when to draw longer run
+ err_adjup, // Increment to err_term for each run drawn
+ err_adjdown; // Subract this from err_term after drawing longer run
+
+ GouraudColor gcol;
+ gcol.r = r0 << GPU_GOURAUD_FIXED_BITS;
+ gcol.g = g0 << GPU_GOURAUD_FIXED_BITS;
+ gcol.b = b0 << GPU_GOURAUD_FIXED_BITS;
+
+ // We use u8 pointers even though PS1 has u16 framebuffer.
+ // This allows pixel-drawing functions to increment dst pointer
+ // directly by the passed 'incr' value, not having to shift it first.
+ u8 *dst = (u8*)gpu_senquack.vram + y0 * dst_stride + x0 * dst_depth;
+
+ // SPECIAL CASE: Vertical line
+ if (dx == 0) {
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ // Get dy fixed-point inverse
+ s32 inv_factor = 1 << GPU_GOURAUD_FIXED_BITS;
+ if (dy > 1) inv_factor = GPU_FAST_DIV(inv_factor, dy);
+
+ // Simultaneously divide and convert integer to Gouraud fixed point:
+ gcol.r_incr = dr * inv_factor;
+ gcol.g_incr = dg * inv_factor;
+ gcol.b_incr = db * inv_factor;
+#else
+ // First, convert to Gouraud fixed point
+ gcol.r_incr = dr << GPU_GOURAUD_FIXED_BITS;
+ gcol.g_incr = dg << GPU_GOURAUD_FIXED_BITS;
+ gcol.b_incr = db << GPU_GOURAUD_FIXED_BITS;
+
+ if (dy > 1) {
+ if (dr) gcol.r_incr /= dy;
+ if (dg) gcol.g_incr /= dy;
+ if (db) gcol.b_incr /= dy;
+ }
+#endif
+
+ gpuPixelSpanDriver(dst, (uintptr_t)&gcol, dst_stride, dy+1);
+ return;
+ }
+
+ // SPECIAL CASE: Horizontal line
+ if (dy == 0) {
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ // Get dx fixed-point inverse
+ s32 inv_factor = (1 << GPU_GOURAUD_FIXED_BITS);
+ if (dx > 1) inv_factor = GPU_FAST_DIV(inv_factor, dx);
+
+ // Simultaneously divide and convert integer to Gouraud fixed point:
+ gcol.r_incr = dr * inv_factor;
+ gcol.g_incr = dg * inv_factor;
+ gcol.b_incr = db * inv_factor;
+#else
+ gcol.r_incr = dr << GPU_GOURAUD_FIXED_BITS;
+ gcol.g_incr = dg << GPU_GOURAUD_FIXED_BITS;
+ gcol.b_incr = db << GPU_GOURAUD_FIXED_BITS;
+
+ if (dx > 1) {
+ if (dr) gcol.r_incr /= dx;
+ if (dg) gcol.g_incr /= dx;
+ if (db) gcol.b_incr /= dx;
+ }
+#endif
+
+ gpuPixelSpanDriver(dst, (uintptr_t)&gcol, sx * dst_depth, dx+1);
+ return;
+ }
+
+ // SPECIAL CASE: Diagonal line
+ if (dx == dy) {
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ // Get dx fixed-point inverse
+ s32 inv_factor = (1 << GPU_GOURAUD_FIXED_BITS);
+ if (dx > 1) inv_factor = GPU_FAST_DIV(inv_factor, dx);
+
+ // Simultaneously divide and convert integer to Gouraud fixed point:
+ gcol.r_incr = dr * inv_factor;
+ gcol.g_incr = dg * inv_factor;
+ gcol.b_incr = db * inv_factor;
+#else
+ // First, convert to Gouraud fixed point
+ gcol.r_incr = dr << GPU_GOURAUD_FIXED_BITS;
+ gcol.g_incr = dg << GPU_GOURAUD_FIXED_BITS;
+ gcol.b_incr = db << GPU_GOURAUD_FIXED_BITS;
+
+ if (dx > 1) {
+ if (dr) gcol.r_incr /= dx;
+ if (dg) gcol.g_incr /= dx;
+ if (db) gcol.b_incr /= dx;
+ }
+#endif
+
+ gpuPixelSpanDriver(dst, (uintptr_t)&gcol, dst_stride + (sx * dst_depth), dy+1);
+ return;
+ }
+
+ int major, minor; // Absolute val of major,minor axis delta
+ ptrdiff_t incr_major, incr_minor; // Ptr increment for each step along axis
+
+ if (dx > dy) {
+ major = dx;
+ minor = dy;
+ } else {
+ major = dy;
+ minor = dx;
+ }
+
+ // Determine if diagonal or horizontal runs
+ if (major < (2 * minor)) {
+ // Diagonal runs, so perform half-octant transformation
+ minor = major - minor;
+
+ // Advance diagonally when drawing runs
+ incr_major = dst_stride + (sx * dst_depth);
+
+ // After drawing each run, correct for over-advance along minor axis
+ if (dx > dy)
+ incr_minor = -dst_stride;
+ else
+ incr_minor = -sx * dst_depth;
+ } else {
+ // Horizontal or vertical runs
+ if (dx > dy) {
+ incr_major = sx * dst_depth;
+ incr_minor = dst_stride;
+ } else {
+ incr_major = dst_stride;
+ incr_minor = sx * dst_depth;
+ }
+ }
+
+#ifdef USE_LINES_ALL_FIXED_PT_MATH
+ s32 major_inv = GPU_FAST_DIV((1 << GPU_GOURAUD_FIXED_BITS), major);
+
+ // Simultaneously divide and convert from integer to Gouraud fixed point:
+ gcol.r_incr = dr * major_inv;
+ gcol.g_incr = dg * major_inv;
+ gcol.b_incr = db * major_inv;
+#else
+ gcol.r_incr = dr ? ((dr << GPU_GOURAUD_FIXED_BITS) / major) : 0;
+ gcol.g_incr = dg ? ((dg << GPU_GOURAUD_FIXED_BITS) / major) : 0;
+ gcol.b_incr = db ? ((db << GPU_GOURAUD_FIXED_BITS) / major) : 0;
+#endif
+
+ if (minor > 1) {
+ // Minimum number of pixels each run
+ min_length = major / minor;
+
+ // Initial error term; reflects an initial step of 0.5 along minor axis
+ err_term = (major % minor) - (minor * 2);
+
+ // Increment err_term this much each step along minor axis; when
+ // err_term crosses zero, draw longer pixel run.
+ err_adjup = (major % minor) * 2;
+ } else {
+ min_length = major;
+ err_term = 0;
+ err_adjup = 0;
+ }
+
+ // Error term adjustment when err_term turns over; used to factor
+ // out the major-axis step made at that time
+ err_adjdown = minor * 2;
+
+ // The initial and last runs are partial, because minor axis advances
+ // only 0.5 for these runs, rather than 1. Each is half a full run,
+ // plus the initial pixel.
+ start_length = end_length = (min_length / 2) + 1;
+
+ if (min_length & 1) {
+ // If there're an odd number of pixels per run, we have 1 pixel that
+ // can't be allocated to either the initial or last partial run, so
+ // we'll add 0.5 to err_term so that this pixel will be handled
+ // by the normal full-run loop
+ err_term += minor;
+ } else {
+ // If the minimum run length is even and there's no fractional advance,
+ // we have one pixel that could go to either the initial or last
+ // partial run, which we'll arbitrarily allocate to the last run
+ if (err_adjup == 0)
+ start_length--; // Leave out the extra pixel at the start
+ }
+
+ // First run of pixels
+ dst = gpuPixelSpanDriver(dst, (uintptr_t)&gcol, incr_major, start_length);
+ dst += incr_minor;
+
+ // Middle runs of pixels
+ while (--minor > 0) {
+ int run_length = min_length;
+ err_term += err_adjup;
+
+ // If err_term passed 0, reset it and draw longer run
+ if (err_term > 0) {
+ err_term -= err_adjdown;
+ run_length++;
+ }
+
+ dst = gpuPixelSpanDriver(dst, (uintptr_t)&gcol, incr_major, run_length);
+ dst += incr_minor;
+ }
+
+ // Final run of pixels
+ gpuPixelSpanDriver(dst, (uintptr_t)&gcol, incr_major, end_length);
+}
+
+#endif /* __GPU_UNAI_GPU_RASTER_LINE_H__ */
notaz.gp2x.de / pcsx_rearmed.git / blobdiff