...

examples/28-sdl-graphics.sx

@@ -10,79 +10,60 @@ vec4 :: (x: f32, y: f32, z: f32, w: f32) -> Vector(4, f32) {
 
 // ---- Matrix44: column-major 4×4 matrix ----
 
-Matrix44 :: struct {
+Matrix44 :: union {
     data: [16]f32;
+    struct { c0, c1, c2, c3: Vector(4, f32); };
 }
 
-mat4_zero :: (m: *Matrix44) {
-    memset(xx @m.data[0], 0, 16 * size_of(f32));
+mat4_multiply :: (a: *Matrix44, b: *Matrix44) -> Matrix44 {
+    out : Matrix44 = ---;
+    out.c0 = a.c0 * b.c0.x + a.c1 * b.c0.y + a.c2 * b.c0.z + a.c3 * b.c0.w;
+    out.c1 = a.c0 * b.c1.x + a.c1 * b.c1.y + a.c2 * b.c1.z + a.c3 * b.c1.w;
+    out.c2 = a.c0 * b.c2.x + a.c1 * b.c2.y + a.c2 * b.c2.z + a.c3 * b.c2.w;
+    out.c3 = a.c0 * b.c3.x + a.c1 * b.c3.y + a.c2 * b.c3.z + a.c3 * b.c3.w;
+    out;
 }
 
-mat4_identity :: (m: *Matrix44) {
-    mat4_zero(m);
-    m.data[0] = 1.0; m.data[5] = 1.0; m.data[10] = 1.0; m.data[15] = 1.0;
-}
-
-mat4_multiply :: (out: *Matrix44, a: *Matrix44, b: *Matrix44) {
-    tmp : [16]f32 = ---;
-    j := 0;
-    while j < 4 {
-        i := 0;
-        while i < 4 {
-            sum : f32 = 0.0;
-            k := 0;
-            while k < 4 {
-                sum = sum + a.data[k * 4 + i] * b.data[j * 4 + k];
-                k += 1;
-            }
-            tmp[j * 4 + i] = sum;
-            i += 1;
-        }
-        j += 1;
-    }
-    out.data = tmp;
-}
-
-mat4_perspective :: (m: *Matrix44, fov: f32, aspect: f32, near: f32, far: f32) {
-    mat4_zero(m);
+mat4_perspective :: (fov: f32, aspect: f32, near: f32, far: f32) -> Matrix44 {
     half := fov / 2.0;
     f := cos(half) / sin(half);
-    m.data[0] = f / aspect;
-    m.data[5] = f;
-    m.data[10] = (far + near) / (near - far);
-    m.data[11] = -1.0;
-    m.data[14] = (2.0 * far * near) / (near - far);
+    m : Matrix44 = ---;
+    m.c0 = vec4(f / aspect, 0.0, 0.0, 0.0);
+    m.c1 = vec4(0.0, f, 0.0, 0.0);
+    m.c2 = vec4(0.0, 0.0, (far + near) / (near - far), -1.0);
+    m.c3 = vec4(0.0, 0.0, (2.0 * far * near) / (near - far), 0.0);
+    m;
 }
 
-mat4_rotate_y :: (m: *Matrix44, angle: f32) {
-    mat4_zero(m);
+mat4_rotate_y :: (angle: f32) -> Matrix44 {
     c := cos(angle);
     s := sin(angle);
-    m.data[0] = c;
-    m.data[2] = 0.0 - s;
-    m.data[5] = 1.0;
-    m.data[8] = s;
-    m.data[10] = c;
-    m.data[15] = 1.0;
+    m : Matrix44 = ---;
+    m.c0 = vec4(c, 0.0, 0.0 - s, 0.0);
+    m.c1 = vec4(0.0, 1.0, 0.0, 0.0);
+    m.c2 = vec4(s, 0.0, c, 0.0);
+    m.c3 = vec4(0.0, 0.0, 0.0, 1.0);
+    m;
 }
 
-mat4_rotate_x :: (m: *Matrix44, angle: f32) {
-    mat4_zero(m);
+mat4_rotate_x :: (angle: f32) -> Matrix44 {
     c := cos(angle);
     s := sin(angle);
-    m.data[0] = 1.0;
-    m.data[5] = c;
-    m.data[6] = s;
-    m.data[9] = 0.0 - s;
-    m.data[10] = c;
-    m.data[15] = 1.0;
+    m : Matrix44 = ---;
+    m.c0 = vec4(1.0, 0.0, 0.0, 0.0);
+    m.c1 = vec4(0.0, c, s, 0.0);
+    m.c2 = vec4(0.0, 0.0 - s, c, 0.0);
+    m.c3 = vec4(0.0, 0.0, 0.0, 1.0);
+    m;
 }
 
-mat4_translate :: (m: *Matrix44, tx: f32, ty: f32, tz: f32) {
-    mat4_identity(m);
-    m.data[12] = tx;
-    m.data[13] = ty;
-    m.data[14] = tz;
+mat4_translate :: (tx: f32, ty: f32, tz: f32) -> Matrix44 {
+    m : Matrix44 = ---;
+    m.c0 = vec4(1.0, 0.0, 0.0, 0.0);
+    m.c1 = vec4(0.0, 1.0, 0.0, 0.0);
+    m.c2 = vec4(0.0, 0.0, 1.0, 0.0);
+    m.c3 = vec4(tx, ty, tz, 1.0);
+    m;
 }
 
 // ---- Shader helpers ----
@@ -295,26 +276,13 @@ GLSL;
         angle := ms * 0.001;
         
         // Build matrices
-        proj : Matrix44 = ---;
-        mat4_perspective(proj, PI / 4.0, 800.0 / 600.0, 0.1, 100.0);
-
-        view : Matrix44 = ---;
-        mat4_translate(view, 0.0, 0.0, -3.0);
-
-        rot_y : Matrix44 = ---;
-        mat4_rotate_y(rot_y, angle);
-
-        rot_x : Matrix44 = ---;
-        mat4_rotate_x(rot_x, angle * 0.7);
-
-        model : Matrix44 = ---;
-        mat4_multiply(model, rot_y, rot_x);
-
-        vm : Matrix44 = ---;
-        mat4_multiply(vm, view, model);
-
-        mvp : Matrix44 = ---;
-        mat4_multiply(mvp, proj, vm);
+        proj  := mat4_perspective(PI / 4.0, 800.0 / 600.0, 0.1, 100.0);
+        view  := mat4_translate(0.0, 0.0, -3.0);
+        rot_y := mat4_rotate_y(angle);
+        rot_x := mat4_rotate_x(angle * 0.7);
+        model := mat4_multiply(rot_y, rot_x);
+        vm    := mat4_multiply(view, model);
+        mvp   := mat4_multiply(proj, vm);
 
         glUniformMatrix4fv(mvp_loc, 1, 0, mvp.data);