feat: started athmospheare post processing

src/athmosphere.h

@@ -0,0 +1,30 @@
+#ifndef ATHMOSPHERE_H
+#define ATHMOSPHERE_H
+
+#include "linmath.h"
+#include "rendertarget.h"
+void renderAthmosphere(render_target *target, const mat4x4 invProj) {
+
+  float widthF = 2. / target->width;
+  float heightF = 2. / target->height;
+
+  for (int y = 0; y < target->height; y++) {
+    for (int x = 0; x < target->width; x++) {
+      vec4 tmp = {((float)x) * widthF - 1.f, ((float)y) * heightF - 1.0f,
+                  ((float)target_get_depth(target, x, y)) / 65536.0f, 1.0f};
+      // vec4_scale(tmp, tmp, 1.0f / tmp[2]);
+
+      vec4 pos;
+      mat4x4_mul_vec4(pos, invProj, tmp);
+      vec4_scale(pos, pos, 1.0f / pos[3]);
+      // pos[2] = -pos[2];
+      vec4_scale(pos, pos, -.1f);
+      // vec4_scale(tmp, tmp, -1.f);
+      // tmp[3] = -tmp[2];
+      vec3_set(pos, pos[2]);
+      target_set_color(target, x, y, pos);
+    }
+  }
+}
+
+#endif

src/main.c

@@ -164,6 +164,17 @@ int main(void) {
     render(&target, &rocket.model, &drawMat, buffer);
     renderC = clock() - renderC;
 
+    mat4x4 invProj;
+    mat4x4_invert(invProj, rData.projMat);
+
+    athmosC = clock();
+    // renderAthmosphere(&target, invProj);
+    athmosC = clock() - athmosC;
+
+    if (didHit(rocket)) {
+      stop = 1;
+    }
+
     base64encode(&target, encodeBuff);
     printf("\033[H");
     printImage(encodeBuff);