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@roxlu /math.cpp Secret
Last active Aug 29, 2015

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Embeddable Matrix Math
#include <stdio.h>
#include <stdlib.h>
/* ---------------------------------------------------------------------------*/
/* Embeddable Math . */
/* For latest version see: https://gist.github.com/roxlu/ed69c74b819f4fc8cf29 */
/* ---------------------------------------------------------------------------*/
static void create_ortho_matrix(float l, float r, float b, float t, float n, float f, float* m);
static void create_identity_matrix(float* m);
static void create_translation_matrix(float x, float y, float z, float* m);
int main() {
/* Create orthographic projection matrix. */
float ortho[16];
float width = 1280.0f;
float height = 720.0f;
create_ortho_matrix(0.0f, width, height, 0.0f, 0.0f, 100.0f, ortho);
float ident[16];
create_identity_matrix(ident);
float translation[16];
create_translation_matrix(10.0f, 10.0f, 0.0f, translation);
return 0;
}
static void create_ortho_matrix(float l, float r, float b, float t, float n, float f, float* m) {
m[1] = 0.0f;
m[2] = 0.0f;
m[3] = 0.0f;
m[4] = 0.0f;
m[6] = 0.0f;
m[7] = 0.0f;
m[8] = 0.0f;
m[9] = 0.0f;
m[11] = 0.0f;
m[15] = 1.0f;
float rml = r - l;
float fmn = f - n;
float tmb = t - b;
m[0] = 2.0f / rml;
m[5] = 2.0f / tmb;
m[10] = -2.0f / fmn;
m[12] = -(r + l) / rml;
m[13] = -(t + b) / tmb;
m[14] = -(f + n) / fmn;
}
static void create_translation_matrix(float x, float y, float z, float* m) {
m[0] = 1.0f; m[4] = 0.0f; m[8] = 0.0f; m[12] = x;
m[1] = 0.0f; m[5] = 1.0f; m[9] = 0.0f; m[13] = y;
m[2] = 0.0f; m[6] = 0.0f; m[10] = 1.0f; m[14] = z;
m[3] = 0.0f; m[7] = 0.0f; m[11] = 0.0f; m[15] = 1.0f;
}
static void create_identity_matrix(float* m) {
m[0] = 1.0f; m[4] = 0.0f; m[8] = 0.0f; m[12] = 0.0f;
m[1] = 0.0f; m[5] = 1.0f; m[9] = 0.0f; m[13] = 0.0f;
m[2] = 0.0f; m[6] = 0.0f; m[10] = 1.0f; m[14] = 0.0f;
m[3] = 0.0f; m[7] = 0.0f; m[11] = 0.0f; m[15] = 1.0f;
}
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