williamjcm/small3dlib
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Add modes

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This commit is contained in:
Miloslav Číž 2018-11-18 18:25:55 +01:00
parent 02b4e5e079
commit 28ce385dad
2 changed files with 65 additions and 9 deletions
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71
s3l.h
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@ -40,9 +40,14 @@ typedef struct
#define S3L_BACKFACE_CULLING_CW 1
#define S3L_BACKFACE_CULLING_CCW 2
#define S3L_MODE_TRIANGLES 0
#define S3L_MODE_LINES 1
#define S3L_MODE_POINTS 2
typedef struct
{
int backfaceCulling;
int mode;
} S3L_DrawConfig;
void S3L_PIXEL_FUNCTION(S3L_PixelInfo *pixel); // forward decl
@ -51,8 +56,8 @@ typedef struct
{
int16_t steps;
int16_t err;
int16_t x;
int16_t y;
S3L_ScreenCoord x;
S3L_ScreenCoord y;
int16_t *majorCoord;
int16_t *minorCoord;
@ -198,17 +203,69 @@ void S3L_drawTriangle(int16_t x0, int16_t y0, int16_t x1, int16_t y1,
return;
}
S3L_ScreenCoord
tPointX, tPointY, // top triangle point coords
lPointX, lPointY, // left triangle point coords
rPointX, rPointY; // right triangle point coords
S3L_PixelInfo p;
p.barycentric0 = 0;
p.barycentric1 = 0;
p.barycentric2 = 0;
// point mode
if (config.mode == S3L_MODE_POINTS)
{
p.x = x0; p.y = y0; p.barycentric0 = S3L_FRACTIONS_PER_UNIT;
p.barycentric1 = 0; p.barycentric2 = 0;
S3L_PIXEL_FUNCTION(&p);
p.x = x1; p.y = y1; p.barycentric0 = 0;
p.barycentric1 = S3L_FRACTIONS_PER_UNIT; p.barycentric2 = 0;
S3L_PIXEL_FUNCTION(&p);
p.x = x2; p.y = y2; p.barycentric0 = 0;
p.barycentric1 = 0; p.barycentric2 = S3L_FRACTIONS_PER_UNIT;
S3L_PIXEL_FUNCTION(&p);
return;
}
// line mode
if (config.mode == S3L_MODE_LINES)
{
S3L_BresenhamState line;
S3L_Unit lineLen;
#define drawLine(p1,p2)\
S3L_bresenhamInit(&line,x##p1,y##p1,x##p2,y##p2);\
p.barycentric0 = 0;\
p.barycentric1 = 0;\
p.barycentric2 = 0;\
lineLen = S3L_nonZero(line.steps);\
do\
{\
p.x = line.x; p.y = line.y;\
p.barycentric##p1 = S3L_interpolateFrom0(\
S3L_FRACTIONS_PER_UNIT,line.steps,lineLen); \
p.barycentric##p2 = S3L_FRACTIONS_PER_UNIT - p.barycentric##p1;\
S3L_PIXEL_FUNCTION(&p);\
} while (S3L_bresenhamStep(&line));
drawLine(0,1)
drawLine(2,0)
drawLine(1,2)
#undef drawLine
return;
}
// triangle mode
S3L_ScreenCoord
tPointX, tPointY, // top triangle point coords
lPointX, lPointY, // left triangle point coords
rPointX, rPointY; // right triangle point coords
S3L_Unit *barycentric0; // bar. coord that gets higher from L to R
S3L_Unit *barycentric1; // bar. coord that gets higher from R to L
S3L_Unit *barycentric2; // bar. coord that gets higher from bottom up

3
testSDL.c
View file

@ -34,8 +34,6 @@ static inline void setPixel(int x, int y, uint8_t red, uint8_t green, uint8_t bl
void drawPixel(S3L_PixelInfo *p)
{
setPixel(p->x,p->y,
p->barycentric0 / ((float) S3L_FRACTIONS_PER_UNIT) * 255,
p->barycentric1 / ((float) S3L_FRACTIONS_PER_UNIT) * 255,
@ -61,6 +59,7 @@ void draw()
S3L_DrawConfig conf;
conf.backfaceCulling = S3L_BACKFACE_CULLING_NONE;
conf.mode = S3L_MODE_TRIANGLES;
for (int c = 0; c < 7; ++c)
{