1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/mesh.c	Sat Sep 20 13:22:53 2014 +0300
     1.3 @@ -0,0 +1,186 @@
     1.4 +#include <stdio.h>
     1.5 +#include <stdlib.h>
     1.6 +#include <string.h>
     1.7 +#include "opengl.h"
     1.8 +#include "mesh.h"
     1.9 +
    1.10 +static void distort_texcoords(float *tc, float aspect, float lens_center_offset, float scale,
    1.11 +		const float *dist_factors);
    1.12 +static float barrel_scale(float rad, const float *k);
    1.13 +
    1.14 +/* let's avoid a glew dependency in the library just for this */
    1.15 +#ifndef GL_ARRAY_BUFFER
    1.16 +#define GL_ARRAY_BUFFER			0x8892
    1.17 +#define GL_ELEMENT_ARRAY_BUFFER 0x8893
    1.18 +#define GL_STATIC_DRAW			0x88E4
    1.19 +#endif
    1.20 +
    1.21 +#if !defined(GL_VERSION_1_5) || !defined(GL_GLEXT_PROTOTYPES)
    1.22 +static void (*glGenBuffers)(GLsizei, GLuint*);
    1.23 +static void (*glDeleteBuffers)(GLsizei, GLuint*);
    1.24 +static void (*glBufferData)(GLenum, unsigned int, const GLvoid*, GLenum);
    1.25 +static void (*glBindBuffer)(GLenum, GLuint);
    1.26 +#endif
    1.27 +
    1.28 +int vrimp_mesh_init(struct mesh *m)
    1.29 +{
    1.30 +	m->prim = GL_TRIANGLES;
    1.31 +
    1.32 +	m->varr = 0;
    1.33 +	m->iarr = 0;
    1.34 +	m->num_verts = m->num_faces = 0;
    1.35 +	m->vbo = m->ibo = 0;
    1.36 +
    1.37 +	if(!glGenBuffers) {
    1.38 +		glGenBuffers = vrimp_glfunc("glGenBuffersARB");
    1.39 +		glDeleteBuffers = vrimp_glfunc("glDeleteBuffersARB");
    1.40 +		glBufferData = vrimp_glfunc("glBufferDataARB");
    1.41 +		glBindBuffer = vrimp_glfunc("glBindBufferARB");
    1.42 +
    1.43 +		if(!(glGenBuffers && glDeleteBuffers && glBufferData && glBindBuffer)) {
    1.44 +			fprintf(stderr, "Failed to load VBO functions\n");
    1.45 +			return -1;
    1.46 +		}
    1.47 +	}
    1.48 +
    1.49 +	return 0;
    1.50 +}
    1.51 +
    1.52 +void vrimp_mesh_destroy(struct mesh *m)
    1.53 +{
    1.54 +	free(m->varr);
    1.55 +	free(m->iarr);
    1.56 +
    1.57 +	if(m->vbo) glDeleteBuffers(1, &m->vbo);
    1.58 +	if(m->ibo) glDeleteBuffers(1, &m->ibo);
    1.59 +}
    1.60 +
    1.61 +void vrimp_mesh_draw(struct mesh *m)
    1.62 +{
    1.63 +	glEnableClientState(GL_VERTEX_ARRAY);
    1.64 +	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    1.65 +
    1.66 +	glBindBuffer(GL_ARRAY_BUFFER, m->vbo);
    1.67 +	glVertexPointer(3, GL_FLOAT, sizeof(struct vertex), 0);
    1.68 +	glTexCoordPointer(2, GL_FLOAT, sizeof(struct vertex), (void*)offsetof(struct vertex, tx));
    1.69 +
    1.70 +	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m->ibo);
    1.71 +	glDrawElements(GL_TRIANGLES, m->num_faces * 3, GL_UNSIGNED_INT, 0);
    1.72 +
    1.73 +	glBindBuffer(GL_ARRAY_BUFFER, 0);
    1.74 +	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    1.75 +
    1.76 +	glDisableClientState(GL_VERTEX_ARRAY);
    1.77 +	glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    1.78 +}
    1.79 +
    1.80 +int vrimp_mesh_barrel_distortion(struct mesh *m, int usub, int vsub, float aspect,
    1.81 +		float lens_center_offset, float scale, const float *dist_factors,
    1.82 +		float tex_scale_x, float tex_scale_y)
    1.83 +{
    1.84 +	int i, j;
    1.85 +	int uverts, vverts;
    1.86 +	int num_verts, num_quads, num_tris;
    1.87 +	struct vertex *varr, *vptr;
    1.88 +	unsigned int *iarr, *iptr;
    1.89 +	float du, dv;
    1.90 +
    1.91 +	uverts = usub + 1;
    1.92 +	vverts = vsub + 1;
    1.93 +
    1.94 +	num_verts = uverts * vverts;
    1.95 +	num_quads = usub * vsub;
    1.96 +	num_tris = num_quads * 2;
    1.97 +
    1.98 +	if(!(varr = malloc(num_verts * sizeof *varr))) {
    1.99 +		return -1;
   1.100 +	}
   1.101 +	if(!(iarr = malloc(num_tris * 3 * sizeof *iarr))) {
   1.102 +		free(varr);
   1.103 +		return -1;
   1.104 +	}
   1.105 +
   1.106 +	du = 1.0 / (float)usub;
   1.107 +	dv = 1.0 / (float)vsub;
   1.108 +
   1.109 +	vptr = varr;
   1.110 +	for(i=0; i<vverts; i++) {
   1.111 +		float v = (float)i * dv;
   1.112 +		float y = 2.0 * v - 1.0;
   1.113 +
   1.114 +		for(j=0; j<uverts; j++) {
   1.115 +			float u = (float)j * du;
   1.116 +			float x = 2.0 * u - 1.0;
   1.117 +			float tc[2];
   1.118 +			tc[0] = u;
   1.119 +			tc[1] = v;
   1.120 +
   1.121 +			distort_texcoords(tc, aspect, lens_center_offset, scale, dist_factors);
   1.122 +
   1.123 +			vptr->x = x;
   1.124 +			vptr->y = y;
   1.125 +			vptr->z = 0;
   1.126 +			vptr->tx = tc[0] * tex_scale_x;
   1.127 +			vptr->ty = tc[1] * tex_scale_y;
   1.128 +			vptr++;
   1.129 +		}
   1.130 +	}
   1.131 +
   1.132 +	iptr = iarr;
   1.133 +	for(i=0; i<vsub; i++) {
   1.134 +		for(j=0; j<usub; j++) {
   1.135 +			*iptr++ = i * uverts + j;
   1.136 +			*iptr++ = (i + 1) * uverts + j;
   1.137 +			*iptr++ = (i + 1) * uverts + (j + 1);
   1.138 +
   1.139 +			*iptr++ = i * uverts + j;
   1.140 +			*iptr++ = (i + 1) * uverts + (j + 1);
   1.141 +			*iptr++ = i * uverts + (j + 1);
   1.142 +		}
   1.143 +	}
   1.144 +
   1.145 +	glGenBuffers(1, &m->vbo);
   1.146 +	glGenBuffers(1, &m->ibo);
   1.147 +	glBindBuffer(GL_ARRAY_BUFFER, m->vbo);
   1.148 +	glBufferData(GL_ARRAY_BUFFER, num_verts * sizeof *varr, varr, GL_STATIC_DRAW);
   1.149 +	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m->ibo);
   1.150 +	glBufferData(GL_ELEMENT_ARRAY_BUFFER, num_tris * 3 * sizeof *iarr, iarr, GL_STATIC_DRAW);
   1.151 +
   1.152 +	m->prim = GL_TRIANGLES;
   1.153 +	m->num_verts = num_verts;
   1.154 +	m->num_faces = num_tris;
   1.155 +	return 0;
   1.156 +}
   1.157 +
   1.158 +static void distort_texcoords(float *tc, float aspect, float lens_center_offset, float scale,
   1.159 +		const float *dist_factors)
   1.160 +{
   1.161 +	/* map tc [0, 1] -> [-1, 1] */
   1.162 +	float ptx = tc[0] * 2.0 - 1.0;
   1.163 +	float pty = tc[1] * 2.0 - 1.0;
   1.164 +	float rad;
   1.165 +
   1.166 +	ptx += lens_center_offset * 2.0;
   1.167 +	pty /= aspect;	/* correct for aspect ratio */
   1.168 +
   1.169 +	rad = barrel_scale(ptx * ptx + pty * pty, dist_factors);
   1.170 +	ptx *= rad;	/* scale the point by the computer distortion radius */
   1.171 +	pty *= rad;
   1.172 +
   1.173 +	ptx /= scale;
   1.174 +	pty /= scale;
   1.175 +
   1.176 +	pty *= aspect;
   1.177 +	ptx -= lens_center_offset * 2.0;
   1.178 +
   1.179 +	/* map back to range [0, 1] */
   1.180 +	tc[0] = ptx * 0.5 + 0.5;
   1.181 +	tc[1] = pty * 0.5 + 0.5;
   1.182 +}
   1.183 +
   1.184 +static float barrel_scale(float rad, const float *k)
   1.185 +{
   1.186 +	float radsq = rad * rad;
   1.187 +	float radquad = radsq * radsq;
   1.188 +	return k[0] + k[1] * radsq + k[2] * radquad + k[3] * radquad * radsq;
   1.189 +}