graphics

commit cd82c62716831100266a005836323ce0838b52b8
parent 1a45b6bbc6dbfefbbf4128122ecba7799f051521
Author: Brian Swetland <swetland@frotz.net>
Date:   Wed,  4 Sep 2013 03:43:14 -0700

matrix: more stuff

Diffstat:
M
common/matrix.cc
 | 
38
++++++++++++++++++++++++--------------
M
common/matrix.h
 | 
23
+++++++++++++++++++++--

2 files changed, 45 insertions(+), 16 deletions(-)
diff --git a/common/matrix.cc b/common/matrix.cc
@@ -98,19 +98,6 @@ void __mat4_set_rotate_z(float m[16], float rad) {
 	m[15] = 1.0;
 }
 
-#if 0
-/* D3D RH Style */
-void __mat4_set_perspective(float m[16], float fov, float a, float zn, float zf) {
-	memset(m, 0, sizeof(float[16]));
-	float ys = 1.0 / tanf(fov / 2.0);
-	float xs = ys / a;
-	m[0] = xs;
-	m[5] = ys;
-	m[10] = zf / (zn - zf);
-	m[11] = -1.0;
-	m[14] = (zn * zf) / (zn - zf);
-}
-#else
 void __mat4_set_perspective(float m[16], float fov, float a, float zn, float zf) {
 	memset(m, 0, sizeof(float[16]));
 	float fn = 1.0f / (zf - zn);
@@ -121,7 +108,6 @@ void __mat4_set_perspective(float m[16], float fov, float a, float zn, float zf)
 	m[11] = -1.0f;
 	m[14] = -2.0f * (zn * zf) * fn;
 }
-#endif
 
 void __mat4_set_ortho(float m[16], float l, float r, float b, float t, float n, float f) {
 	memset(m, 0, sizeof(float[16]));
@@ -134,3 +120,27 @@ void __mat4_set_ortho(float m[16], float l, float r, float b, float t, float n, 
 	m[15] = 1.0;
 }
 
+/* per gluLookAt docs */
+mat4& mat4::lookAt(const vec3& eye, const vec3& center, const vec3& up) {
+	vec3 f = (center - eye).normalize();
+	vec3 upn = up;
+	vec3 s = cross(f, upn);
+	vec3 u = cross(s, f);
+	m[0] = s[0];
+	m[1] = u[0];
+	m[2] = -f[0];
+	m[3] = 0.0f;
+	m[4] = s[1];
+	m[5] = u[1];
+	m[6] = -f[1];
+	m[7] = 0.0f;
+	m[8] = s[2];
+	m[9] = u[2];
+	m[10] = -f[2];
+	m[11] = 0.0f;
+	m[12] = 0.0f;
+	m[13] = 0.0f;
+	m[14] = 0.0f;
+	m[15] = 1.0f;
+	return *this;
+}
diff --git a/common/matrix.h b/common/matrix.h
@@ -96,6 +96,11 @@ public:
 	float dot(const vec4& v) {
 		return x*v.x + y*v.y + z*v.z + w*v.w;
 	}
+	vec4& normalize(void) {
+		float n = 1.0f / length();
+		x *= n; y *= n; z *= n; w *= n;
+		return *this;
+	}
 };
 
 inline vec4 operator*(const vec4& v, const float n) {
@@ -158,6 +163,11 @@ public:
 	float dot(const vec4& v) {
 		return x*v.x + y*v.y + z*v.z;
 	}
+	vec3& normalize(void) {
+		float n = 1.0f / length();
+		x *= n; y *= n; z *= n;
+		return *this;
+	}
 };
 
 inline vec3 operator*(const vec3& v, const float n) {
@@ -172,7 +182,9 @@ inline vec3 operator+(const vec3& a, const vec3& b) {
 inline vec3 operator-(const vec3& a, const vec3& b) {
 	return vec3(a.x - b.x, a.y - b.y, a.z - b.z);
 }
-
+inline vec3 cross(const vec3& p, const vec3& q) {
+	return vec3(p.y*q.z-p.z*q.y, p.z*q.x-p.x*q.z, p.x*q.y-p.y*q.x);
+}
 
 class mat4 {
 	float m[16];
@@ -244,7 +256,14 @@ public:
 		__mat4_set_perspective(m, fov, aspect, znear, zfar);
 		return *this;
 	};
-
+	mat4& lookAt(const vec3& eye, const vec3& center, const vec3& up); 
+	mat4& camera(const vec3& eye, const vec3& center, const vec3& up) {
+		lookAt(eye, center, up);
+		m[12] = -eye.x;
+		m[13] = -eye.y;
+		m[14] = -eye.z;
+		return *this;
+	}
 	friend vec4 operator*(const mat4& a, const vec4& b);
 
 	mat4& mul(mat4& left, mat4& right) {