3D cube render, basic interpolation, culling

2022-02-13 12:23:13 +01:00
commit d69180dbe6
9 changed files with 8528 additions and 0 deletions
--- a/math.h
+++ b/math.h
@@ -0,0 +1,179 @@
+#include "main.h"
+#include <math.h>
+#include <stdint.h>
+
+struct Mat4 {
+  float p[4][4];
+};
+
+union Vec3 {
+  struct { float x, y, z; };
+  struct { float r, g, b; };
+};
+
+union Vec4 {
+  struct { float x, y, z, w; };
+  struct { float r, g, b, a; };
+  struct { Vec3 xyz; };
+};
+
+FUNCTION
+Mat4 Mat4Identity() {
+  Mat4 result = {
+    1,0,0,0,
+    0,1,0,0,
+    0,0,1,0,
+    0,0,0,1,
+  };
+  return result;
+}
+
+FUNCTION
+Mat4 Mat4RotationZ(float rotation) {
+  float s = sinf(rotation);
+  float c = cosf(rotation);
+  Mat4 result = {
+    c, s, 0, 0,
+    -s,  c, 0, 0,
+    0,  0, 1, 0,
+    0,  0, 0, 1,
+  };
+  return result;
+}
+
+FUNCTION
+Mat4 Mat4RotationY(float rotation) {
+  float s = sinf(rotation);
+  float c = cosf(rotation);
+  Mat4 result = {
+    c, 0, -s, 0,
+    0, 1,  0, 0,
+    s, 0,  c, 0,
+    0, 0,  0, 1,
+  };
+  return result;
+}
+
+FUNCTION
+Mat4 Mat4RotationX(float rotation) {
+  float s = sinf(rotation);
+  float c = cosf(rotation);
+  Mat4 result = {
+    1,  0, 0, 0,
+    0,  c, s, 0,
+    0,  -s, c, 0,
+    0,  0, 0, 1,
+  };
+  return result;
+}
+
+FUNCTION
+Mat4 Mat4Translate(Mat4 a, Vec3 translation) {
+  a.p[0][0] += translation.x;
+  a.p[0][1] += translation.y;
+  a.p[0][2] += translation.z;
+  return a;
+}
+
+FUNCTION
+Vec4 operator-(Vec4 a, Vec4 b) {
+  Vec4 result = {
+    a.x - b.x,
+    a.y - b.y,
+    a.z - b.z,
+    a.w - b.w
+  };
+  return result;
+}
+
+FUNCTION
+Vec4 operator+(Vec4 a, Vec4 b) {
+  Vec4 result = {
+    a.x + b.x,
+    a.y + b.y,
+    a.z + b.z,
+    a.w + b.w
+  };
+  return result;
+}
+
+FUNCTION
+Vec3 operator-(Vec3 a, Vec3 b) {
+  Vec3 result = {
+    a.x - b.x,
+    a.y - b.y,
+    a.z - b.z,
+  };
+  return result;
+}
+
+FUNCTION
+Vec3 operator+(Vec3 a, Vec3 b) {
+  Vec3 result = {
+    a.x + b.x,
+    a.y + b.y,
+    a.z + b.z,
+  };
+  return result;
+}
+
+
+FUNCTION
+Vec4 operator*(Mat4 a, Vec4 b) {
+  Vec4 result = {
+    a.p[0][0] * b.x + a.p[0][1] * b.y + a.p[0][2] * b.z + a.p[0][3] * b.w,
+    a.p[1][0] * b.x + a.p[1][1] * b.y + a.p[1][2] * b.z + a.p[1][3] * b.w,
+    a.p[2][0] * b.x + a.p[2][1] * b.y + a.p[2][2] * b.z + a.p[2][3] * b.w,
+    a.p[3][0] * b.x + a.p[3][1] * b.y + a.p[3][2] * b.z + a.p[3][3] * b.w,
+  };
+  return result;
+}
+
+FUNCTION
+Vec3 operator*(Mat4 a, Vec3 b) {
+  Vec4 result= {
+    a.p[0][0] * b.x + a.p[0][1] * b.y + a.p[0][2] * b.z + a.p[0][3] * 1,
+    a.p[1][0] * b.x + a.p[1][1] * b.y + a.p[1][2] * b.z + a.p[1][3] * 1,
+    a.p[2][0] * b.x + a.p[2][1] * b.y + a.p[2][2] * b.z + a.p[2][3] * 1,
+    a.p[3][0] * b.x + a.p[3][1] * b.y + a.p[3][2] * b.z + a.p[3][3] * 1,
+  };
+  ASSERT(result.w == 1);
+  return result.xyz;
+}
+
+FUNCTION
+Mat4 operator*(Mat4 a, Mat4 b) {
+  Mat4 result;
+  for (int y = 0; y < 4; y++) {
+    for (int x = 0; x < 4; x++) {
+      result.p[y][x] = a.p[y][0] * b.p[0][x] + a.p[y][1] * b.p[1][x] + a.p[y][2] * b.p[2][x] + a.p[y][3] * b.p[3][x];
+    }
+  }
+  return result;
+}
+
+FUNCTION
+float Dot(Vec3 a, Vec3 b) {
+  float result = a.x * b.x + a.y * b.y + a.z * b.z;
+  return result;
+}
+
+FUNCTION
+Vec3 Cross(Vec3 a, Vec3 b) {
+  Vec3 result = {
+    a.y * b.z - a.z * b.y,
+    a.z * b.x - a.x * b.z,
+    a.x * b.y - a.y * b.x,
+  };
+  return result;
+}
+
+FUNCTION
+uint32_t ColorToU32ARGB(Vec4 a) {
+  uint8_t r8 = (uint8_t)(a.r * 255.f + 0.5f);
+  uint8_t g8 = (uint8_t)(a.g * 255.f + 0.5f);
+  uint8_t b8 = (uint8_t)(a.b * 255.f + 0.5f);
+  uint8_t a8 = (uint8_t)(a.a * 255.f + 0.5f);
+  uint32_t result = a8 << 24 | r8 << 16 | g8 << 8 | b8;
+  return result;
+}