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-rw-r--r--progs/glsl/bitmap.c323
1 files changed, 323 insertions, 0 deletions
diff --git a/progs/glsl/bitmap.c b/progs/glsl/bitmap.c
new file mode 100644
index 0000000000..d488ec6cb9
--- /dev/null
+++ b/progs/glsl/bitmap.c
@@ -0,0 +1,323 @@
+/**
+ * Implement glRasterPos + glBitmap with textures + shaders.
+ * Brian Paul
+ * 14 May 2007
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/gl.h>
+#include <GL/glut.h>
+#include <GL/glext.h>
+#include "extfuncs.h"
+#include "shaderutil.h"
+
+
+static GLuint FragShader;
+static GLuint VertShader;
+static GLuint Program;
+
+static GLint Win = 0;
+static GLint WinWidth = 500, WinHeight = 500;
+static GLboolean Anim = GL_TRUE;
+static GLboolean Bitmap = GL_FALSE;
+static GLfloat Xrot = 20.0f, Yrot = 70.0f;
+static GLint uTex, uScale;
+static GLuint Textures[2];
+
+#define TEX_WIDTH 16
+#define TEX_HEIGHT 8
+
+
+static void
+BitmapText(const char *s)
+{
+ while (*s) {
+ glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+ s++;
+ }
+}
+
+
+static void
+Redisplay(void)
+{
+ static const GLfloat px[3] = { 1.2, 0, 0};
+ static const GLfloat nx[3] = {-1.2, 0, 0};
+
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ glPushMatrix();
+ glRotatef(Xrot, 1.0f, 0.0f, 0.0f);
+ glRotatef(Yrot, 0.0f, 1.0f, 0.0f);
+
+ glEnable(GL_LIGHTING);
+
+ glPushMatrix();
+ glScalef(0.5, 0.5, 0.5);
+ glutSolidDodecahedron();
+ glPopMatrix();
+
+ glDisable(GL_LIGHTING);
+
+ glColor3f(0, 1, 0);
+ glBegin(GL_LINES);
+ glVertex3f(-1, 0, 0);
+ glVertex3f( 1, 0, 0);
+ glEnd();
+
+ glColor3f(1, 1, 0);
+
+ if (Bitmap) {
+ glRasterPos3fv(px);
+ BitmapText("+X");
+ glRasterPos3fv(nx);
+ BitmapText("-X");
+ }
+ else {
+ glUseProgram_func(Program);
+
+ /* vertex positions (deltas) depend on texture size and window size */
+ if (uScale != -1) {
+ glUniform2f_func(uScale,
+ 2.0 * TEX_WIDTH / WinWidth,
+ 2.0 * TEX_HEIGHT / WinHeight);
+ }
+
+ /* draw +X */
+ glBindTexture(GL_TEXTURE_2D, Textures[0]);
+ glBegin(GL_QUADS);
+ glTexCoord2f(0, 0); glVertex3fv(px);
+ glTexCoord2f(1, 0); glVertex3fv(px);
+ glTexCoord2f(1, 1); glVertex3fv(px);
+ glTexCoord2f(0, 1); glVertex3fv(px);
+ glEnd();
+
+ /* draw -X */
+ glBindTexture(GL_TEXTURE_2D, Textures[1]);
+ glBegin(GL_QUADS);
+ glTexCoord2f(0, 0); glVertex3fv(nx);
+ glTexCoord2f(1, 0); glVertex3fv(nx);
+ glTexCoord2f(1, 1); glVertex3fv(nx);
+ glTexCoord2f(0, 1); glVertex3fv(nx);
+ glEnd();
+
+ glUseProgram_func(0);
+ }
+
+ glPopMatrix();
+
+ glutSwapBuffers();
+}
+
+
+static void
+Idle(void)
+{
+ Yrot = glutGet(GLUT_ELAPSED_TIME) * 0.01;
+ glutPostRedisplay();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+ WinWidth = width;
+ WinHeight = height;
+ glViewport(0, 0, width, height);
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+ glTranslatef(0.0f, 0.0f, -10.0f);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+ (void) x;
+ (void) y;
+
+ switch(key) {
+ case ' ':
+ case 'a':
+ Anim = !Anim;
+ if (Anim)
+ glutIdleFunc(Idle);
+ else
+ glutIdleFunc(NULL);
+ break;
+ case 'b':
+ Bitmap = !Bitmap;
+ if (Bitmap)
+ printf("Using glBitmap\n");
+ else
+ printf("Using billboard texture\n");
+ break;
+ case 27:
+ glDeleteShader_func(FragShader);
+ glDeleteShader_func(VertShader);
+ glDeleteProgram_func(Program);
+ glutDestroyWindow(Win);
+ exit(0);
+ }
+ glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+ const GLfloat step = 0.125f;
+ switch(key) {
+ case GLUT_KEY_UP:
+ Xrot -= step;
+ break;
+ case GLUT_KEY_DOWN:
+ Xrot += step;
+ break;
+ case GLUT_KEY_LEFT:
+ Yrot -= step;
+ break;
+ case GLUT_KEY_RIGHT:
+ Yrot += step;
+ break;
+ }
+ /*printf("Xrot: %f Yrot: %f\n", Xrot, Yrot);*/
+ glutPostRedisplay();
+}
+
+
+static void
+MakeTexImage(const char *p, GLuint texobj)
+{
+ GLubyte image[TEX_HEIGHT][TEX_WIDTH];
+ GLuint i, j, k;
+
+ for (i = 0; i < TEX_HEIGHT; i++) {
+ for (j = 0; j < TEX_WIDTH; j++) {
+ k = i * TEX_WIDTH + j;
+ if (p[k] == ' ') {
+ image[i][j] = 0;
+ }
+ else {
+ image[i][j] = 255;
+ }
+ }
+ }
+
+ glBindTexture(GL_TEXTURE_2D, texobj);
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_INTENSITY, TEX_WIDTH, TEX_HEIGHT, 0,
+ GL_RED, GL_UNSIGNED_BYTE, image);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+}
+
+
+static void
+MakeBitmapTextures(void)
+{
+ const char *px =
+ " X X "
+ " X X X "
+ " X X X "
+ " XXXXX X "
+ " X X X "
+ " X X X "
+ " X X "
+ " X X ";
+ const char *nx =
+ " X X "
+ " X X "
+ " X X "
+ " XXXXX X "
+ " X X "
+ " X X "
+ " X X "
+ " X X ";
+ glGenTextures(2, Textures);
+ MakeTexImage(px, Textures[0]);
+ MakeTexImage(nx, Textures[1]);
+}
+
+
+static void
+Init(void)
+{
+ /* Fragment shader: modulate raster color by texture, discard fragments
+ * with alpha < 1.0
+ */
+ static const char *fragShaderText =
+ "uniform sampler2D tex2d; \n"
+ "void main() {\n"
+ " vec4 c = texture2D(tex2d, gl_TexCoord[0].xy); \n"
+ " if (c.w < 1.0) \n"
+ " discard; \n"
+ " gl_FragColor = c * gl_Color; \n"
+ "}\n";
+ /* Vertex shader: compute new vertex position based on incoming vertex pos,
+ * texcoords and special scale factor.
+ */
+ static const char *vertShaderText =
+ "uniform vec2 scale; \n"
+ "void main() {\n"
+ " vec4 p = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+ " gl_Position.xy = p.xy + gl_MultiTexCoord0.xy * scale * p.w; \n"
+ " gl_Position.zw = p.zw; \n"
+ " gl_TexCoord[0] = gl_MultiTexCoord0; \n"
+ " gl_FrontColor = gl_Color; \n"
+ "}\n";
+
+ if (!ShadersSupported())
+ exit(1);
+
+ GetExtensionFuncs();
+
+ VertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText);
+ FragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText);
+ Program = LinkShaders(VertShader, FragShader);
+
+ glUseProgram_func(Program);
+
+ uScale = glGetUniformLocation_func(Program, "scale");
+ uTex = glGetUniformLocation_func(Program, "tex2d");
+ if (uTex != -1) {
+ glUniform1i_func(uTex, 0); /* tex unit 0 */
+ }
+
+ glUseProgram_func(0);
+
+ glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
+ glEnable(GL_DEPTH_TEST);
+ glEnable(GL_NORMALIZE);
+ glEnable(GL_LIGHT0);
+
+ MakeBitmapTextures();
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ glutInit(&argc, argv);
+ glutInitWindowSize(WinWidth, WinHeight);
+ glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+ Win = glutCreateWindow(argv[0]);
+ glutReshapeFunc(Reshape);
+ glutKeyboardFunc(Key);
+ glutSpecialFunc(SpecialKey);
+ glutDisplayFunc(Redisplay);
+ if (Anim)
+ glutIdleFunc(Idle);
+ Init();
+ glutMainLoop();
+ return 0;
+}
+
+
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