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add look_at() and built-in stack to GLMatrix

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This commit is contained in:
Josh Holtrop 2012-09-10 21:20:59 -04:00
parent a9c99fbe4a
commit 05dfd6f8a7
2 changed files with 104 additions and 23 deletions
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101
src/client/GL/GLMatrix.cc
View File

@ -5,12 +5,32 @@
const GLMatrix GLMatrix::Identity;
GLMatrix::GLMatrix()
static void normalize(GLfloat * vec)
{
set_identity();
GLfloat len = sqrtf(vec[0] * vec[0] + vec[1] * vec[1] + vec[2] * vec[2]);
vec[0] /= len;
vec[1] /= len;
vec[2] /= len;
}
void GLMatrix::set_identity()
static void cross(GLfloat * out, GLfloat * in1, GLfloat * in2)
{
out[0] = in1[1] * in2[2] - in1[2] * in2[1];
out[1] = in1[2] * in2[0] - in1[0] * in2[2];
out[2] = in1[0] * in2[1] - in1[1] * in2[0];
}
GLMatrix::GLMatrix()
{
load_identity();
}
GLMatrix::GLMatrix(const GLMatrix & orig)
{
memcpy(&m_mat, &orig.m_mat, sizeof(m_mat));
}
void GLMatrix::load_identity()
{
memset(m_mat, 0, sizeof(m_mat));
for (int i = 0; i < 4; i++)
@ -94,33 +114,62 @@ void GLMatrix::rotate(GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
void GLMatrix::frustum(GLfloat left, GLfloat right,
GLfloat bottom, GLfloat top,
GLfloat near, GLfloat far)
GLfloat z_near, GLfloat z_far)
{
GLMatrix mult;
GLfloat rl = right - left;
GLfloat tb = top - bottom;
GLfloat fn = far - near;
mult.m_mat[0][0] = 2 * near / rl;
GLfloat fn = z_far - z_near;
mult.m_mat[0][0] = 2 * z_near / rl;
mult.m_mat[2][0] = (right + left) / rl;
mult.m_mat[1][1] = 2 * near / tb;
mult.m_mat[1][1] = 2 * z_near / tb;
mult.m_mat[2][1] = (top + bottom) / tb;
mult.m_mat[2][2] = - (far + near) / fn;
mult.m_mat[3][2] = - 2 * far * near / fn;
mult.m_mat[2][2] = - (z_far + z_near) / fn;
mult.m_mat[3][2] = - 2 * z_far * z_near / fn;
mult.m_mat[2][3] = -1.0;
mult.m_mat[3][3] = 0.0f;
multiply(mult);
}
void GLMatrix::look_at(GLfloat eye_x, GLfloat eye_y, GLfloat eye_z,
GLfloat center_x, GLfloat center_y, GLfloat center_z,
GLfloat up_x, GLfloat up_y, GLfloat up_z)
{
GLfloat forward[3], side[3], up[3];
forward[0] = center_x - eye_x;
forward[1] = center_y - eye_y;
forward[2] = center_z - eye_z;
normalize(forward);
up[0] = up_x;
up[1] = up_y;
up[2] = up_z;
cross(side, forward, up);
normalize(side);
cross(up, side, forward);
GLMatrix mult;
mult.m_mat[0][0] = side[0];
mult.m_mat[0][1] = side[1];
mult.m_mat[0][2] = side[2];
mult.m_mat[1][0] = up[0];
mult.m_mat[1][1] = up[1];
mult.m_mat[1][2] = up[2];
mult.m_mat[2][0] = -forward[0];
mult.m_mat[2][1] = -forward[1];
mult.m_mat[2][2] = -forward[2];
multiply(mult);
translate(-eye_x, -eye_y, -eye_z);
}
void GLMatrix::perspective(GLfloat fovy, GLfloat aspect,
GLfloat near, GLfloat far)
GLfloat z_near, GLfloat z_far)
{
GLMatrix mult;
GLfloat f = 1.0 / tan(M_PI * fovy / 360.0);
GLfloat nf = near - far;
GLfloat nf = z_near - z_far;
mult.m_mat[0][0] = f / aspect;
mult.m_mat[1][1] = f;
mult.m_mat[2][2] = (far + near) / nf;
mult.m_mat[3][2] = (2 * far * near) / nf;
mult.m_mat[2][2] = (z_far + z_near) / nf;
mult.m_mat[3][2] = (2 * z_far * z_near) / nf;
mult.m_mat[2][3] = -1.0;
mult.m_mat[3][3] = 0.0f;
multiply(mult);
@ -128,17 +177,37 @@ void GLMatrix::perspective(GLfloat fovy, GLfloat aspect,
void GLMatrix::ortho(GLfloat left, GLfloat right,
GLfloat bottom, GLfloat top,
GLfloat near, GLfloat far)
GLfloat z_near, GLfloat z_far)
{
GLMatrix mult;
GLfloat rl = right - left;
GLfloat tb = top - bottom;
GLfloat fn = far - near;
GLfloat fn = z_far - z_near;
mult.m_mat[0][0] = 2 / rl;
mult.m_mat[3][0] = - (right + left) / rl;
mult.m_mat[1][1] = 2 / tb;
mult.m_mat[3][1] = - (top + bottom) / tb;
mult.m_mat[2][2] = -2 / fn;
mult.m_mat[3][2] = - (far + near) / fn;
mult.m_mat[3][2] = - (z_far + z_near) / fn;
multiply(mult);
}
void GLMatrix::to_uniform(GLint uniform)
{
glUniformMatrix4fv(uniform, 1, GL_TRUE, &m_mat[0][0]);
}
void GLMatrix::push()
{
m_stack.push(Mat4_s());
memcpy(&m_stack.top().mat, &m_mat, sizeof(m_mat));
}
void GLMatrix::pop()
{
if (m_stack.size() > 0)
{
memcpy(&m_mat, &m_stack.top().mat, sizeof(m_mat));
m_stack.pop();
}
}

26
src/client/GL/GLMatrix.h
View File

@ -2,10 +2,11 @@
#ifndef GLMATRIX_H
#define GLMATRIX_H
#include <GL/glew.h>
#include GL_INCLUDE_FILE
#include <stack>
/**
* Store a 4x4 matrix of GLfloats with associated operations.
* Store a 4x4 matrix of floats with associated operations.
*
* Matrices are stored in column-major order.
*/
@ -13,26 +14,37 @@ class GLMatrix
{
public:
GLMatrix();
void set_identity();
GLMatrix(const GLMatrix & orig);
void load_identity();
void translate(GLfloat x, GLfloat y, GLfloat z);
void scale(GLfloat x, GLfloat y, GLfloat z);
void rotate(GLfloat angle, GLfloat x, GLfloat y, GLfloat z);
void multiply(const GLMatrix & other);
void frustum(GLfloat left, GLfloat right,
GLfloat bottom, GLfloat top,
GLfloat near, GLfloat far);
GLfloat z_near, GLfloat z_far);
void look_at(GLfloat eye_x, GLfloat eye_y, GLfloat eye_z,
GLfloat center_x, GLfloat center_y, GLfloat center_z,
GLfloat up_x, GLfloat up_y, GLfloat up_z);
void perspective(GLfloat fovy, GLfloat aspect,
GLfloat near, GLfloat far);
GLfloat z_near, GLfloat z_far);
void ortho(GLfloat left, GLfloat right,
GLfloat bottom, GLfloat top,
GLfloat near, GLfloat far);
GLfloat z_near, GLfloat z_far);
void to_uniform(GLint uniform);
void push();
void pop();
friend GLMatrix operator*(const GLMatrix &, const GLMatrix &);
static const GLMatrix Identity;
protected:
GLfloat m_mat[4][4];
typedef GLfloat Mat4[4][4];
Mat4 m_mat;
struct Mat4_s { Mat4 mat; };
std::stack<Mat4_s> m_stack;
};
#endif