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-rw-r--r--src/maths/maths.h118
1 files changed, 96 insertions, 22 deletions
diff --git a/src/maths/maths.h b/src/maths/maths.h
index 3301634..217f2e0 100644
--- a/src/maths/maths.h
+++ b/src/maths/maths.h
@@ -9,6 +9,7 @@
#pragma once
#include <math.h>
+#include <stdio.h>
#include "maths_types.h"
// --- Helpers
@@ -20,7 +21,7 @@
// Dimension 3
static inline vec3 vec3_create(f32 x, f32 y, f32 z) { return (vec3){ x, y, z }; }
-#define vec3(x, y, z) (vec3_create(x, y, z))
+#define vec3(x, y, z) ((vec3){ x, y, z })
static inline vec3 vec3_add(vec3 a, vec3 b) { return (vec3){ a.x + b.x, a.y + b.y, a.z + b.z }; }
static inline vec3 vec3_sub(vec3 a, vec3 b) { return (vec3){ a.x - b.x, a.y - b.y, a.z - b.z }; }
static inline vec3 vec3_mult(vec3 a, f32 s) { return (vec3){ a.x * s, a.y * s, a.z * s }; }
@@ -48,10 +49,16 @@ static inline vec3 vec3_cross(vec3 a, vec3 b) {
#define VEC3_Z ((vec3){ .x = 0.0, .y = 0.0, .z = 1.0 })
#define VEC3_NEG_Z ((vec3){ .x = 0.0, .y = 0.0, .z = -1.0 })
+static inline void print_vec3(vec3 v) { printf("{ x: %f, y: %f, z: %f )\n", v.x, v.y, v.z); }
+
// TODO: Dimension 2
static inline vec2 vec2_create(f32 x, f32 y) { return (vec2){ x, y }; }
+#define vec2(x, y) ((vec2){ x, y })
+static inline vec2 vec2_div(vec2 a, f32 s) { return (vec2){ a.x / s, a.y / s }; }
// TODO: Dimension 4
+static inline vec4 vec4_create(f32 x, f32 y, f32 z, f32 w) { return (vec4){ x, y, z, w }; }
+#define vec4(x, y, z, w) (vec4_create(x, y, z, w))
#define VEC4_ZERO ((vec4){ .x = 0.0, .y = 0.0, .z = 0.0, .w = 0.0 })
// --- Quaternion Implementations
@@ -78,6 +85,52 @@ static quat quat_from_axis_angle(vec3 axis, f32 angle, bool normalize) {
return q;
}
+// TODO: grok this.
+static inline quat quat_slerp(quat a, quat b, f32 percentage) {
+ quat out_quaternion;
+
+ quat q0 = quat_normalise(a);
+ quat q1 = quat_normalise(b);
+
+ // Compute the cosine of the angle between the two vectors.
+ f32 dot = quat_dot(q0, q1);
+
+ // If the dot product is negative, slerp won't take
+ // the shorter path. Note that v1 and -v1 are equivalent when
+ // the negation is applied to all four components. Fix by
+ // reversing one quaternion.
+ if (dot < 0.0f) {
+ q1.x = -q1.x;
+ q1.y = -q1.y;
+ q1.z = -q1.z;
+ q1.w = -q1.w;
+ dot = -dot;
+ }
+
+ const f32 DOT_THRESHOLD = 0.9995f;
+ if (dot > DOT_THRESHOLD) {
+ // If the inputs are too close for comfort, linearly interpolate
+ // and normalize the result.
+ out_quaternion =
+ (quat){ q0.x + ((q1.x - q0.x) * percentage), q0.y + ((q1.y - q0.y) * percentage),
+ q0.z + ((q1.z - q0.z) * percentage), q0.w + ((q1.w - q0.w) * percentage) };
+
+ return quat_normalise(out_quaternion);
+ }
+
+ // Since dot is in range [0, DOT_THRESHOLD], acos is safe
+ f32 theta_0 = cos(dot); // theta_0 = angle between input vectors
+ f32 theta = theta_0 * percentage; // theta = angle between v0 and result
+ f32 sin_theta = sin(theta); // compute this value only once
+ f32 sin_theta_0 = sin(theta_0); // compute this value only once
+
+ f32 s0 = cos(theta) - dot * sin_theta / sin_theta_0; // == sin(theta_0 - theta) / sin(theta_0)
+ f32 s1 = sin_theta / sin_theta_0;
+
+ return (quat){ (q0.x * s0) + (q1.x * s1), (q0.y * s0) + (q1.y * s1), (q0.z * s0) + (q1.z * s1),
+ (q0.w * s0) + (q1.w * s1) };
+}
+
// --- Matrix Implementations
static inline mat4 mat4_ident() {
@@ -139,6 +192,43 @@ static inline mat4 mat4_mult(mat4 lhs, mat4 rhs) {
return out_matrix;
}
+static mat4 mat4_transposed(mat4 matrix) {
+ mat4 out_matrix = mat4_ident();
+ out_matrix.data[0] = matrix.data[0];
+ out_matrix.data[1] = matrix.data[4];
+ out_matrix.data[2] = matrix.data[8];
+ out_matrix.data[3] = matrix.data[12];
+ out_matrix.data[4] = matrix.data[1];
+ out_matrix.data[5] = matrix.data[5];
+ out_matrix.data[6] = matrix.data[9];
+ out_matrix.data[7] = matrix.data[13];
+ out_matrix.data[8] = matrix.data[2];
+ out_matrix.data[9] = matrix.data[6];
+ out_matrix.data[10] = matrix.data[10];
+ out_matrix.data[11] = matrix.data[14];
+ out_matrix.data[12] = matrix.data[3];
+ out_matrix.data[13] = matrix.data[7];
+ out_matrix.data[14] = matrix.data[11];
+ out_matrix.data[15] = matrix.data[15];
+ return out_matrix;
+}
+
+#if defined(CEL_REND_BACKEND_VULKAN)
+/** @brief Creates a perspective projection matrix compatible with Vulkan */
+static inline mat4 mat4_perspective(f32 fov_radians, f32 aspect_ratio, f32 near_clip,
+ f32 far_clip) {
+ f32 half_tan_fov = tanf(fov_radians * 0.5f);
+ mat4 out_matrix = { .data = { 0 } };
+
+ out_matrix.data[0] = 1.0f / (aspect_ratio * half_tan_fov);
+ out_matrix.data[5] = -1.0f / half_tan_fov; // Flip Y-axis for Vulkan
+ out_matrix.data[10] = -((far_clip + near_clip) / (far_clip - near_clip));
+ out_matrix.data[11] = -1.0f;
+ out_matrix.data[14] = -((2.0f * far_clip * near_clip) / (far_clip - near_clip));
+
+ return out_matrix;
+}
+#else
/** @brief Creates a perspective projection matrix */
static inline mat4 mat4_perspective(f32 fov_radians, f32 aspect_ratio, f32 near_clip,
f32 far_clip) {
@@ -151,6 +241,7 @@ static inline mat4 mat4_perspective(f32 fov_radians, f32 aspect_ratio, f32 near_
out_matrix.data[14] = -((2.0f * far_clip * near_clip) / (far_clip - near_clip));
return out_matrix;
}
+#endif
/** @brief Creates an orthographic projection matrix */
static inline mat4 mat4_orthographic(f32 left, f32 right, f32 bottom, f32 top, f32 near_clip,
@@ -210,7 +301,7 @@ static inline mat4 mat4_look_at(vec3 position, vec3 target, vec3 up) {
#define TRANSFORM_DEFAULT \
((transform){ .position = VEC3_ZERO, \
- .rotation = (quat){ .x = 0., .y = 0., .z = 0., .w = 0. }, \
+ .rotation = (quat){ .x = 0., .y = 0., .z = 0., .w = 1. }, \
.scale = 1.0, \
.is_dirty = false })
@@ -219,10 +310,10 @@ static transform transform_create(vec3 pos, quat rot, f32 scale) {
}
static inline mat4 transform_to_mat(transform *tf) {
- mat4 trans = mat4_translation(tf->position);
- mat4 rot = mat4_rotation(tf->rotation);
mat4 scale = mat4_scale(tf->scale);
- return mat4_mult(trans, mat4_mult(rot, scale));
+ mat4 rotation = mat4_rotation(tf->rotation);
+ mat4 translation = mat4_translation(tf->position);
+ return mat4_mult(translation, mat4_mult(rotation, scale));
}
// --- Sizing asserts
@@ -231,20 +322,3 @@ _Static_assert(alignof(vec3) == 4, "vec3 is 4 byte aligned");
_Static_assert(sizeof(vec3) == 12, "vec3 is 12 bytes so has no padding");
_Static_assert(alignof(vec4) == 4, "vec4 is 4 byte aligned");
-
-// --- Some other types
-typedef struct u32x3 {
- union {
- struct {
- u32 x;
- u32 y;
- u32 z;
- };
- struct {
- u32 r;
- u32 g;
- u32 b;
- };
- };
-} u32x3;
-#define u32x3(x, y, z) ((u32x3){ x, y, z })
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-01-10 18:41:25 +0000