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Add z-buffer
This commit is contained in:
Miloslav Číž
parent
c11cc70238
commit
4c4ced2d77
2 changed files with 60 additions and 99 deletions
92
s3l.h
92
s3l.h
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@ -125,31 +125,6 @@
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on. */
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#endif
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#ifndef S3L_RENDER_STRATEGY
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#define S3L_RENDER_STRATEGY S3L_STRATEGY_Z_BUFFER /**< Strategy used for
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visibility
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determination -- see
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S3L_STRATEGY_*
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consts. */
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#endif
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#define S3L_STRATEGY_NONE 0 /**< No strategy -- can be sufficient in
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some cases. */
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#define S3L_STRATEGY_Z_BUFFER 1 /**< Use z-buffer (depth buffer).
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Accurate and fast, but requires a lot
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of memory. */
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#define S3L_STRATEGY_BACK_TO_FRONT 2 /**< Sort and draw triangles from back to
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front (painter's algorithm). Requires
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less memory, but can be slower than
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Z-buffer and can't handle
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intersecting triangles. */
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#define S3L_STRATEGY_FRONT_TO_BACK 3 /**< Sort and draw triangles from front to
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back (reverse painter's algorithm).
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Requires a bit more memory than back
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to front, but can also be faster
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(doesn't draw over already drawn
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pixels). */
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#ifndef S3L_MAX_TRIANGES_DRAWN
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#define S3L_MAX_TRIANGES_DRAWN 128 /**< Maximum number of triangles that can
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be drawn in sorted modes. This
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@ -188,6 +163,20 @@ typedef int32_t S3L_Unit; /**< Units of measurement in 3D space. There is
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typedef int16_t S3L_ScreenCoord;
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typedef uint16_t S3L_Index;
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#ifndef S3L_USE_Z_BUFFER
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#define S3L_USE_Z_BUFFER 1 /**< Whether to use z-buffer (depth buffer) for
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visibility determination. This is accurate
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and can be fast, but requires a lot of
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memory. */
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#endif
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#define S3L_MAX_DEPTH 2147483647
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#if S3L_USE_Z_BUFFER
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#define S3L_COMPUTE_DEPTH 1
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S3L_Unit S3L_zBuffer[S3L_RESOLUTION_X * S3L_RESOLUTION_Y];
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#endif
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#ifndef S3L_NEAR
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#define S3L_NEAR (S3L_FRACTIONS_PER_UNIT / 4) /**< Distance of the near
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clipping plane. */
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@ -492,6 +481,8 @@ void S3L_drawTriangle(
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const S3L_Camera *camera,
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S3L_Index triangleID);
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void S3L_zBufferClear();
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static inline void S3L_rotate2DPoint(S3L_Unit *x, S3L_Unit *y, S3L_Unit angle);
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//=============================================================================
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@ -1149,6 +1140,30 @@ void S3L_mapProjectionPlaneToScreen(
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(point.y * S3L_HALF_RESOLUTION_X) / S3L_FRACTIONS_PER_UNIT;
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}
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static inline int8_t S3L_zTest(
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S3L_ScreenCoord x,
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S3L_ScreenCoord y,
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S3L_Unit depth)
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{
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uint32_t index = y * S3L_RESOLUTION_X + x;
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if (depth < S3L_zBuffer[index])
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{
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S3L_zBuffer[index] = depth;
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return 1;
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}
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return 0;
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}
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void S3L_zBufferClear()
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{
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#if S3L_USE_Z_BUFFER
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for (uint32_t i = 0; i < S3L_RESOLUTION_X * S3L_RESOLUTION_Y; ++i)
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S3L_zBuffer[i] = S3L_MAX_DEPTH;
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#endif
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}
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void _S3L_drawFilledTriangle(
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S3L_Vec4 point0,
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S3L_Vec4 point1,
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@ -1464,37 +1479,44 @@ void _S3L_drawFilledTriangle(
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for (S3L_ScreenCoord x = lXClipped; x < rXClipped; ++x)
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{
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p->x = x;
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#if S3L_PERSPECTIVE_CORRECTION == 1
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S3L_Unit rowT =
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S3L_correctPerspective(S3L_interpolateFrom0(S3L_FRACTIONS_PER_UNIT,
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x - lX,rowLength),&rowPC);
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#endif
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#if S3L_COMPUTE_DEPTH
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#if S3L_PERSPECTIVE_CORRECTION == 1
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p->depth = S3L_interpolateByUnit(lDepth,rDepth,rowT);
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#else
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p->depth = S3L_getFastLerpValue(depthFLS);
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S3L_stepFastLerp(depthFLS);
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#endif
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#endif
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#if S3L_USE_Z_BUFFER
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if (!S3L_zTest(p->x,p->y,p->depth))
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continue;
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#endif
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#if S3L_PERSPECTIVE_CORRECTION == 1
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*barycentric0 =
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S3L_interpolateByUnitFrom0(rT,rowT);
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*barycentric1 =
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S3L_interpolateByUnitFrom0(lT,S3L_FRACTIONS_PER_UNIT - rowT);
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#if S3L_COMPUTE_DEPTH
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p->depth = S3L_interpolateByUnit(lDepth,rDepth,rowT);
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#endif
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#else
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*barycentric0 = S3L_getFastLerpValue(b0FLS);
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*barycentric1 = S3L_getFastLerpValue(b1FLS);
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S3L_stepFastLerp(b0FLS);
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S3L_stepFastLerp(b1FLS);
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#if S3L_COMPUTE_LERP_DEPTH
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p->depth = S3L_getFastLerpValue(depthFLS);
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S3L_stepFastLerp(depthFLS);
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#endif
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#endif
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*barycentric2 = S3L_FRACTIONS_PER_UNIT - *barycentric0 - *barycentric1;
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p->x = x;
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S3L_PIXEL_FUNCTION(p);
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}
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} // y clipping
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67
testSDL.c
67
testSDL.c
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@ -7,6 +7,8 @@
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#include <stdio.h>
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#include <math.h>
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#define S3L_USE_Z_BUFFER 1
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#define S3L_PIXEL_FUNCTION drawPixel
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#define S3L_RESOLUTION_X 640
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@ -134,17 +136,7 @@ S3L_DrawConfig conf;
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void draw()
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{
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/*
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if (frame % 128 == 0)
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{
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printf("frame: %d\n",frame);
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printf("scene.camera:\n");
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printf(" translation: ");
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S3L_writeVec4(scene.camera.transform.translation);
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printf(" rotation: ");
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S3L_writeVec4(scene.camera.transform.rotation);
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}
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*/
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S3L_zBufferClear();
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offScreenPixels = 0;
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@ -155,63 +147,10 @@ void draw()
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scene.models[0].transform.rotation.z = f * 0.1;
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scene.models[0].transform.rotation.x = f * 0.3;
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// modelTransform.translation.x = sin(f >> 7) * 700;
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// modelTransform.translation.y = sin(f >> 8) * 600;
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/*
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S3L_drawModelIndexed(ver,tri,12,modelTransform,&scene.camera,&conf);
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modelTransform.translation.x += 2 * S3L_FRACTIONS_PER_UNIT;
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S3L_drawModelIndexed(ver,tri,12,modelTransform,&scene.camera,&conf);
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modelTransform.translation.x -= 2 * S3L_FRACTIONS_PER_UNIT;
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*/
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S3L_drawScene(scene);
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if (offScreenPixels > 0)
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printf("offscreen pixels: %d\n",offScreenPixels);
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// S3L_drawModelIndexed(ver,tri,1,modelTransform,&scene.camera,&conf);
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/*
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conf.backfaceCulling = S3L_BACKFACE_CULLING_NONE;
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conf.mode = S3L_MODE_TRIANGLES;
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for (int c = 0; c < 8; ++c)
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{
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int
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x0 = test_coords[6 * c],
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y0 = test_coords[6 * c + 1],
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x1 = test_coords[6 * c + 2],
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y1 = test_coords[6 * c + 3],
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x2 = test_coords[6 * c + 4],
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y2 = test_coords[6 * c + 5];
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int cent = (x0 + x1 + x2) / 3.0;
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x2 = cent + (x2 - cent) * sin(frame * 0.001) * 2;
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//x2 = cent + (x2 - cent) * sin(600 * 0.001) * 2;
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S3L_drawTriangle(x0,y0,x1,y1,x2,y2,conf,0);
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setPixel(x0,y0,255,0,0);
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setPixel(x1,y1,255,0,0);
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setPixel(x2,y2,255,0,0);
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}
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float rotRate = 0.002;
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int16_t rotX0 = 200 + sin(frame * rotRate) * 100;
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int16_t rotY0 = 200 + cos(frame * rotRate) * 100;
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int16_t rotX1 = 200 + sin((frame + 1500) * rotRate) * 100;
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int16_t rotY1 = 200 + cos((frame + 1500) * rotRate) * 100;
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int16_t rotX2 = 200 + sin((frame + 500) * rotRate) * 100;
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int16_t rotY2 = 200 + cos((frame + 500) * rotRate) * 100;
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S3L_drawTriangle(rotX0,rotY0,rotX1,rotY1,rotX2,rotY2,conf,0);
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*/
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}
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int main()
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