413 lines
10 KiB
C
413 lines
10 KiB
C
/**
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* Test multi-texturing with GL shading language.
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*
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* Copyright (C) 2008 Brian Paul All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <assert.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <GL/glew.h>
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#include "GL/glut.h"
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#include "readtex.h"
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#include "shaderutil.h"
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static const char *Demo = "multitex";
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static const char *VertFile = "multitex.vert";
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static const char *FragFile = "multitex.frag";
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static const char *TexFiles[2] =
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{
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"../images/tile.rgb",
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"../images/tree2.rgba"
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};
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static GLuint Program;
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static GLfloat Xrot = 0.0, Yrot = .0, Zrot = 0.0;
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static GLfloat EyeDist = 10;
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static GLboolean Anim = GL_TRUE;
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static GLboolean UseArrays = GL_TRUE;
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static GLboolean UseVBO = GL_TRUE;
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static GLuint VBO = 0;
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static GLint VertCoord_attr = -1, TexCoord0_attr = -1, TexCoord1_attr = -1;
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/* value[0] = tex unit */
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static struct uniform_info Uniforms[] = {
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{ "tex1", 1, GL_SAMPLER_2D, { 0, 0, 0, 0 }, -1 },
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{ "tex2", 1, GL_SAMPLER_2D, { 1, 0, 0, 0 }, -1 },
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END_OF_UNIFORMS
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};
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static const GLfloat Tex0Coords[4][2] = {
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{ 0.0, 0.0 }, { 2.0, 0.0 }, { 2.0, 2.0 }, { 0.0, 2.0 }
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};
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static const GLfloat Tex1Coords[4][2] = {
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{ 0.0, 0.0 }, { 1.0, 0.0 }, { 1.0, 1.0 }, { 0.0, 1.0 }
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};
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static const GLfloat VertCoords[4][2] = {
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{ -3.0, -3.0 }, { 3.0, -3.0 }, { 3.0, 3.0 }, { -3.0, 3.0 }
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};
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static void
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SetupVertexBuffer(void)
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{
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glGenBuffersARB(1, &VBO);
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glBindBufferARB(GL_ARRAY_BUFFER_ARB, VBO);
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glBufferDataARB(GL_ARRAY_BUFFER_ARB,
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sizeof(VertCoords) +
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sizeof(Tex0Coords) +
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sizeof(Tex1Coords),
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NULL,
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GL_STATIC_DRAW_ARB);
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/* non-interleaved vertex arrays */
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glBufferSubDataARB(GL_ARRAY_BUFFER_ARB,
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0, /* offset */
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sizeof(VertCoords), /* size */
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VertCoords); /* data */
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glBufferSubDataARB(GL_ARRAY_BUFFER_ARB,
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sizeof(VertCoords), /* offset */
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sizeof(Tex0Coords), /* size */
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Tex0Coords); /* data */
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glBufferSubDataARB(GL_ARRAY_BUFFER_ARB,
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sizeof(VertCoords) +
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sizeof(Tex0Coords), /* offset */
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sizeof(Tex1Coords), /* size */
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Tex1Coords); /* data */
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glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
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}
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static void
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DrawPolygonArray(void)
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{
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void *vertPtr, *tex0Ptr, *tex1Ptr;
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if (UseVBO) {
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glBindBufferARB(GL_ARRAY_BUFFER_ARB, VBO);
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vertPtr = (void *) 0;
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tex0Ptr = (void *) sizeof(VertCoords);
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tex1Ptr = (void *) (sizeof(VertCoords) + sizeof(Tex0Coords));
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}
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else {
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glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
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vertPtr = VertCoords;
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tex0Ptr = Tex0Coords;
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tex1Ptr = Tex1Coords;
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}
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if (VertCoord_attr >= 0) {
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glVertexAttribPointer(VertCoord_attr, 2, GL_FLOAT, GL_FALSE,
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0, vertPtr);
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glEnableVertexAttribArray(VertCoord_attr);
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}
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else {
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glVertexPointer(2, GL_FLOAT, 0, vertPtr);
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glEnableClientState(GL_VERTEX_ARRAY);
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}
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glVertexAttribPointer(TexCoord0_attr, 2, GL_FLOAT, GL_FALSE,
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0, tex0Ptr);
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glEnableVertexAttribArray(TexCoord0_attr);
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glVertexAttribPointer(TexCoord1_attr, 2, GL_FLOAT, GL_FALSE,
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0, tex1Ptr);
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glEnableVertexAttribArray(TexCoord1_attr);
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glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
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glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
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}
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static void
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DrawPolygonVert(void)
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{
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GLuint i;
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glBegin(GL_TRIANGLE_FAN);
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for (i = 0; i < 4; i++) {
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glVertexAttrib2fv(TexCoord0_attr, Tex0Coords[i]);
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glVertexAttrib2fv(TexCoord1_attr, Tex1Coords[i]);
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if (VertCoord_attr >= 0)
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glVertexAttrib2fv(VertCoord_attr, VertCoords[i]);
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else
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glVertex2fv(VertCoords[i]);
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}
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glEnd();
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}
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static void
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draw(void)
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glPushMatrix(); /* modelview matrix */
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glTranslatef(0.0, 0.0, -EyeDist);
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glRotatef(Zrot, 0, 0, 1);
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glRotatef(Yrot, 0, 1, 0);
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glRotatef(Xrot, 1, 0, 0);
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if (UseArrays)
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DrawPolygonArray();
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else
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DrawPolygonVert();
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glPopMatrix();
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glutSwapBuffers();
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}
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static void
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idle(void)
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{
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GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME);
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Yrot = t;
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glutPostRedisplay();
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}
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static void
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key(unsigned char k, int x, int y)
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{
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(void) x;
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(void) y;
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switch (k) {
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case 'a':
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UseArrays = !UseArrays;
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printf("Arrays: %d\n", UseArrays);
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break;
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case 'v':
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UseVBO = !UseVBO;
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printf("Use VBO: %d\n", UseVBO);
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break;
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case ' ':
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Anim = !Anim;
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if (Anim)
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glutIdleFunc(idle);
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else
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glutIdleFunc(NULL);
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break;
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case 'z':
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EyeDist -= 0.5;
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if (EyeDist < 3.0)
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EyeDist = 3.0;
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break;
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case 'Z':
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EyeDist += 0.5;
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if (EyeDist > 90.0)
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EyeDist = 90;
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break;
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case 27:
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exit(0);
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}
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glutPostRedisplay();
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}
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static void
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specialkey(int key, int x, int y)
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{
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GLfloat step = 2.0;
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(void) x;
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(void) y;
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switch (key) {
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case GLUT_KEY_UP:
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Xrot += step;
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break;
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case GLUT_KEY_DOWN:
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Xrot -= step;
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break;
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case GLUT_KEY_LEFT:
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Yrot -= step;
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break;
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case GLUT_KEY_RIGHT:
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Yrot += step;
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break;
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}
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glutPostRedisplay();
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}
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/* new window size or exposure */
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static void
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Reshape(int width, int height)
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{
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GLfloat ar = (float) width / (float) height;
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glViewport(0, 0, (GLint)width, (GLint)height);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glFrustum(-2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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}
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static void
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InitTextures(void)
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{
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GLenum filter = GL_LINEAR;
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int i;
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for (i = 0; i < 2; i++) {
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GLint imgWidth, imgHeight;
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GLenum imgFormat;
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GLubyte *image = NULL;
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image = LoadRGBImage(TexFiles[i], &imgWidth, &imgHeight, &imgFormat);
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if (!image) {
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printf("Couldn't read %s\n", TexFiles[i]);
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exit(0);
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}
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glActiveTexture(GL_TEXTURE0 + i);
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glBindTexture(GL_TEXTURE_2D, 42 + i);
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gluBuild2DMipmaps(GL_TEXTURE_2D, 4, imgWidth, imgHeight,
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imgFormat, GL_UNSIGNED_BYTE, image);
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free(image);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
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}
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}
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static GLuint
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CreateProgram(const char *vertProgFile, const char *fragProgFile,
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struct uniform_info *uniforms)
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{
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GLuint fragShader, vertShader, program;
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vertShader = CompileShaderFile(GL_VERTEX_SHADER, vertProgFile);
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fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, fragProgFile);
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assert(vertShader);
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program = LinkShaders(vertShader, fragShader);
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glUseProgram(program);
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SetUniformValues(program, uniforms);
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PrintUniforms(Uniforms);
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assert(ValidateShaderProgram(program));
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VertCoord_attr = glGetAttribLocation(program, "VertCoord");
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if (VertCoord_attr > 0) {
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/* We want the VertCoord attrib to have position zero so that
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* the call to glVertexAttrib(0, xyz) triggers vertex processing.
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* Otherwise, if TexCoord0 or TexCoord1 gets position 0 we'd have
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* to set that attribute last (which is a PITA to manage).
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*/
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glBindAttribLocation(program, 0, "VertCoord");
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/* re-link */
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glLinkProgram(program);
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/* VertCoord_attr should be zero now */
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VertCoord_attr = glGetAttribLocation(program, "VertCoord");
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assert(VertCoord_attr == 0);
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}
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TexCoord0_attr = glGetAttribLocation(program, "TexCoord0");
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TexCoord1_attr = glGetAttribLocation(program, "TexCoord1");
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printf("TexCoord0_attr = %d\n", TexCoord0_attr);
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printf("TexCoord1_attr = %d\n", TexCoord1_attr);
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printf("VertCoord_attr = %d\n", VertCoord_attr);
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return program;
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}
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static void
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InitPrograms(void)
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{
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Program = CreateProgram(VertFile, FragFile, Uniforms);
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}
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static void
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InitGL(void)
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{
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if (!ShadersSupported())
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exit(1);
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printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
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printf("Usage:\n");
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printf(" a - toggle arrays vs. immediate mode rendering\n");
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printf(" v - toggle VBO usage for array rendering\n");
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printf(" z/Z - change viewing distance\n");
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printf(" SPACE - toggle animation\n");
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printf(" Esc - exit\n");
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InitTextures();
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InitPrograms();
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SetupVertexBuffer();
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glEnable(GL_DEPTH_TEST);
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glClearColor(.6, .6, .9, 0);
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glColor3f(1.0, 1.0, 1.0);
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}
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int
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main(int argc, char *argv[])
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{
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glutInit(&argc, argv);
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glutInitWindowSize(500, 400);
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glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
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glutCreateWindow(Demo);
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glewInit();
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glutReshapeFunc(Reshape);
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glutKeyboardFunc(key);
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glutSpecialFunc(specialkey);
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glutDisplayFunc(draw);
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if (Anim)
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glutIdleFunc(idle);
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InitGL();
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glutMainLoop();
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return 0;
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}
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