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/*
* Copyright © 2009 Eric Anholt
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Authors:
* Eric Anholt <eric@anholt.net>
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <err.h>
#include <errno.h>
#include <assert.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <getopt.h>
#include "glass.h"
extern int no_multi_draw_arrays;
extern GLUvec4 eye_world;
static GLUmat4 world_to_light_eye;
GLUmat4 world_to_light_ndc, world_to_shadow_texcoords;
GLuint shadow_tex = 0, shadow_fbo;
static void
set_world_to_shadow_transform(void)
{
GLUmat4 temp;
/* Setup the viewport translation to map light NDC to texcoords.
*/
memcpy(&temp, &gluIdentityMatrix, sizeof(gluIdentityMatrix));
temp.col[0].values[0] = (1.0 - 0.0) / 2.0;
temp.col[3].values[0] = temp.col[0].values[0] + 0.0;
temp.col[1].values[1] = (1.0 - 0.0) / 2.0;
temp.col[3].values[1] = temp.col[1].values[1] + 0.0;
temp.col[2].values[2] = (1.0 - 0.0) / 2.0;
temp.col[3].values[2] = (1.0 - 0.0) / 2.0;
gluMult4m_4m(&world_to_shadow_texcoords, &temp, &world_to_light_ndc);
}
static void
calculate_light_projection(void)
{
GLUvec4 light_up;
GLUmat4 temp;
GLUvec4 light_to_rings;
/* Wrong. So wrong. */
light_up.values[0] = 1.0;
light_up.values[1] = 0.0;
light_up.values[2] = 0.0;
light_up.values[3] = 1.0;
/*
print_GLUvec4("light_world", &light_world);
print_GLUvec4("ring_center", &ring_bounding_sphere_center_world);
print_GLUvec4("light_up ", &light_up);
*/
/* Our shadow mapping can't handle lights inside the frustum of the
* shadow casters.
*/
gluSub4v_4v(&light_to_rings,
&ring_bounding_sphere_center_world, &light_world);
/* Transform for looking from they eye's point of view at the pile of
* rings.
*/
gluLookAt4v(&world_to_light_eye,
&light_world,
&ring_bounding_sphere_center_world,
&light_up);
make_sphere_frustum(&temp, &light_to_rings,
ring_bounding_sphere_radius);
/*print_GLUmat4("frustum", &temp);*/
gluMult4m_4m(&world_to_light_ndc, &temp, &world_to_light_eye);
}
/* The ground plane is located in world coordinates, so no need to do any
* object_to_world transformation.
*/
static void
install_shadow_transform(int instance)
{
GLUmat4 mvp;
gluMult4m_4m(&mvp, &world_to_light_ndc, &ring_obj_to_world[instance]);
glUniformMatrix4fv(shadow_uniforms[SHADOW_UNIFORM_MVP].location, 1, 0,
(float *)&mvp);
}
void
generate_rings_shadowmap(void)
{
int instance;
int shadow_width = 1024, shadow_height = 1024;
GLboolean first_time = GL_FALSE;
if (shadow_prog == 0)
return;
glUseProgram(shadow_prog);
calculate_light_projection();
if (shadow_tex == 0) {
glGenTextures(1, &shadow_tex);
glBindTexture(GL_TEXTURE_2D, shadow_tex);
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_COMPARE_MODE,
GL_COMPARE_R_TO_TEXTURE);
glTexParameteri(GL_TEXTURE_2D,
GL_TEXTURE_COMPARE_FUNC,
GL_LEQUAL);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
shadow_width, shadow_height, 0,
GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glGenFramebuffersEXT(1, &shadow_fbo);
glBindFramebuffer(GL_FRAMEBUFFER_EXT, shadow_fbo);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,
GL_DEPTH_ATTACHMENT_EXT,
GL_TEXTURE_2D,
shadow_tex,
0);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
first_time = GL_TRUE;
}
glBindFramebuffer(GL_FRAMEBUFFER_EXT, shadow_fbo);
glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
/* Move the faces away from the light, so that if they're compared
* for being lit, they'll tend to pass.
*/
glPolygonOffset(2, 2);
glEnable(GL_POLYGON_OFFSET_FILL);
if (first_time) {
GLenum status;
status = glCheckFramebufferStatusEXT (GL_FRAMEBUFFER_EXT);
if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
fprintf(stderr, "shadow map FBO incomplete: 0x%08x\n",
status);
}
glViewport(0, 0, shadow_width, shadow_height);
/* Clear to the material color. */
glClear(GL_DEPTH_BUFFER_BIT);
/* Draw the rings in black. */
glBindVertexArray(ring.shadow_array_obj);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER_ARB, ring.vbo);
for (instance = 0; instance < NUM_RINGS; instance++) {
install_shadow_transform(instance);
do_ring_drawelements();
}
glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);
glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
glDisable(GL_POLYGON_OFFSET_FILL);
set_world_to_shadow_transform();
}
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