Module refactoring

submodules/RMIntro/Sources/core/matrix.h

@@ -0,0 +1,100 @@
+#include "linmath.h"
+#include <math.h>
+#include <string.h>
+
+/* Adapted from Android's OpenGL Matrix.java. */
+
+static inline void mat4x4_perspective(mat4x4 m, float y_fov_in_degrees, float aspect, float n, float f)
+{
+	const float angle_in_radians = (float) (y_fov_in_degrees * M_PI / 180.0);
+	const float a = (float) (1.0 / tan(angle_in_radians / 2.0));
+
+	m[0][0] = a / aspect;
+	m[1][0] = 0.0f;
+	m[2][0] = 0.0f;
+	m[3][0] = 0.0f;
+
+	m[1][0] = 0.0f;
+	m[1][1] = a;
+	m[1][2] = 0.0f;
+	m[1][3] = 0.0f;
+
+	m[2][0] = 0.0f;
+	m[2][1] = 0.0f;
+	m[2][2] = -((f + n) / (f - n));
+	m[2][3] = -1.0f;
+
+	m[3][0] = 0.0f;
+	m[3][1] = 0.0f;
+	m[3][2] = -((2.0f * f * n) / (f - n));
+	m[3][3] = 0.0f;
+}
+
+static inline void mat4x4_translate_in_place(mat4x4 m, float x, float y, float z)
+{
+	int i;
+    for (i = 0; i < 4; ++i) {
+        m[3][i] += m[0][i] * x
+        		+  m[1][i] * y
+        		+  m[2][i] * z;
+    }
+}
+
+static inline void mat4x4_look_at(mat4x4 m,
+		float eyeX, float eyeY, float eyeZ,
+		float centerX, float centerY, float centerZ,
+		float upX, float upY, float upZ)
+{
+	// See the OpenGL GLUT documentation for gluLookAt for a description
+	// of the algorithm. We implement it in a straightforward way:
+
+	float fx = centerX - eyeX;
+	float fy = centerY - eyeY;
+	float fz = centerZ - eyeZ;
+
+	// Normalize f
+	vec3 f_vec = {fx, fy, fz};
+	float rlf = 1.0f / vec3_len(f_vec);
+	fx *= rlf;
+	fy *= rlf;
+	fz *= rlf;
+
+	// compute s = f x up (x means "cross product")
+	float sx = fy * upZ - fz * upY;
+	float sy = fz * upX - fx * upZ;
+	float sz = fx * upY - fy * upX;
+
+	// and normalize s
+	vec3 s_vec = {sx, sy, sz};
+	float rls = 1.0f / vec3_len(s_vec);
+	sx *= rls;
+	sy *= rls;
+	sz *= rls;
+
+	// compute u = s x f
+	float ux = sy * fz - sz * fy;
+	float uy = sz * fx - sx * fz;
+	float uz = sx * fy - sy * fx;
+
+	m[0][0] = sx;
+	m[0][1] = ux;
+	m[0][2] = -fx;
+	m[0][3] = 0.0f;
+
+	m[1][0] = sy;
+	m[1][1] = uy;
+	m[1][2] = -fy;
+	m[1][3] = 0.0f;
+
+	m[2][0] = sz;
+	m[2][1] = uz;
+	m[2][2] = -fz;
+	m[2][3] = 0.0f;
+
+	m[3][0] = 0.0f;
+	m[3][1] = 0.0f;
+	m[3][2] = 0.0f;
+	m[3][3] = 1.0f;
+
+	mat4x4_translate_in_place(m, -eyeX, -eyeY, -eyeZ);
+}