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Calculating the max bounds better

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Krzosa Karol
2022-02-17 10:48:32 +01:00
parent 8d4a747e1f
commit 512dba64cb
3 changed files with 66 additions and 28 deletions
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48
main.cpp
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@@ -26,14 +26,6 @@ OK Basic linear transformations - rotation, translation, scaling
#include "math.h"
#include "stb_image.h"
// TODO:
// Perspective correct interpolation
// Camera
// Perspective projection
// Texture mapping
// Reading OBJ
struct Face {
int p[3];
Vec2 tex[3];
@@ -88,20 +80,22 @@ float EdgeFunction(Vec4 vecp0, Vec4 vecp1, Vec4 p) {
FUNCTION
void DrawTriangle(Image* dst, Image *src, Vec4 p0, Vec4 p1, Vec4 p2,
Vec2 tex0, Vec2 tex1, Vec2 tex2) {
float min_x = (float)(MIN(p0.x, MIN(p1.x, p2.x)));
float min_y = (float)(MIN(p0.y, MIN(p1.y, p2.y)));
float max_x = (float)(MAX(p0.x, MAX(p1.x, p2.x)));
float max_y = (float)(MAX(p0.y, MAX(p1.y, p2.y)));
min_x = MAX(0, min_x) + 0.5f;
min_y = MAX(0, min_y) + 0.5f;
max_x = MIN(dst->x-1, max_x) + 0.5f;
max_y = MIN(dst->y-1, max_y) + 0.5f;
float min_x1 = (float)(MIN(p0.x, MIN(p1.x, p2.x)));
float min_y1 = (float)(MIN(p0.y, MIN(p1.y, p2.y)));
float max_x1 = (float)(MAX(p0.x, MAX(p1.x, p2.x)));
float max_y1 = (float)(MAX(p0.y, MAX(p1.y, p2.y)));
int min_x = (int)MAX(0, floorf(min_x1));
int min_y = (int)MAX(0, floorf(min_y1));
int max_x = (int)MIN(dst->x, ceilf(max_x1));
int max_y = (int)MIN(dst->y, ceilf(max_y1));
//@Todo: Fix the proper rounding
//@Todo: Determine whether we need subprecision etc
float area = EdgeFunction(p0, p1, p2);
for (int y = min_y; y < max_y; y++) {
for (int x = min_x; x < max_x; x++) {
int xi = (int)(x + 0.5f);
int yi = (int)(y + 0.5f);
float edge1 = EdgeFunction(p0, p1, { (float)x,(float)y });
float edge2 = EdgeFunction(p1, p2, { (float)x,(float)y });
float edge3 = EdgeFunction(p2, p0, { (float)x,(float)y });
@@ -110,6 +104,8 @@ void DrawTriangle(Image* dst, Image *src, Vec4 p0, Vec4 p1, Vec4 p2,
float w1 = edge2 / area;
float w2 = edge3 / area;
float w3 = edge1 / area;
float x_diff = xi - x;
float y_diff = yi - y;
#if 1
float u = tex0.x * (w1 / p0.w) + tex1.x * (w2 / p1.w) + tex2.x * (w3 / p2.w);
float v = tex0.y * (w1 / p0.w) + tex1.y * (w2 / p1.w) + tex2.y * (w3 / p2.w);
@@ -122,10 +118,20 @@ void DrawTriangle(Image* dst, Image *src, Vec4 p0, Vec4 p1, Vec4 p2,
float v = tex0.y * w1 + tex1.y * w2 + tex2.y * w3;
#endif
int ui = (int)(u * (src->x - 1) + 0.5f);
int vi = (int)(v * (src->y - 1) + 0.5f);
uint32_t pixel = src->pixels[ui + (src->y - 1 - vi) * src->x];
dst->pixels[x + (dst->y - 1 - y) * dst->x] = pixel;
int ui = (int)(u * (src->x - 2) + 0.5f);
int vi = (int)(v * (src->y - 2) + 0.5f);
uint32_t *pixel = src->pixels + (ui + (src->y - 1 - vi) * src->x);
Vec4 pixelx1y1 = V4ABGR(*pixel);
Vec4 pixelx2y1 = V4ABGR(*(pixel + 1));
Vec4 pixelx1y2 = V4ABGR(*(pixel - src->x));
Vec4 pixelx2y2 = V4ABGR(*(pixel + 1 - src->x));
Vec4 blendx1 = Lerp(pixelx1y1, pixelx2y1, x_diff);
Vec4 blendx2 = Lerp(pixelx1y2, pixelx2y2, x_diff);
Vec4 result_color = Lerp(blendx1, blendx2, y_diff);
uint32_t color32 = ColorToU32ARGB(pixelx1y1);
dst->pixels[xi + (dst->y - 1 - yi) * dst->x] = color32;
}
}
}
@@ -153,7 +159,7 @@ void DrawLine(Image *dst, float x0, float y0, float x1, float y1) {
}
int main() {
OS_Init({.window_x=1280, .window_y=720});
OS_Init({ 1280,720 });
float rotation = 0;
Vec3 camera_pos = {0,0,-5};
int x,y,n;