Initial revision

1 files changed, 295 insertions, 0 deletions

diff --git a/progs/samples/blendeq.c b/progs/samples/blendeq.c
new file mode 100644
index 00000000000..7be52073ab0
--- /dev/null
+++ b/progs/samples/blendeq.c
@@ -0,0 +1,295 @@
+/*
+** blendeq.c - Demonstrates the use of the blend_minmax, blend_subtract,
+**    and blend_logic_op extensions using glBlendEquationEXT.
+**
+**    Over a two-color backround, draw rectangles using twelve blend
+**    options.  The values are read back as UNSIGNED_BYTE and printed
+**    in hex over each value.  These values are useful for logic
+**    op comparisons when channels are 8 bits deep.
+*/
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <GL/glut.h>
+
+
+GLenum doubleBuffer;
+static int dithering = 0;
+static int doPrint = 1;
+static int deltaY;
+GLint windW, windH;
+
+static void DrawString(const char *string)
+{
+    int i;
+
+    for (i = 0; string[i]; i++)
+	glutBitmapCharacter(GLUT_BITMAP_9_BY_15, string[i]);
+}
+
+static void Init(void)
+{
+
+    glDisable(GL_DITHER);
+    glShadeModel(GL_FLAT);
+}
+
+static void Reshape(int width, int height)
+{
+
+    windW = (GLint)width;
+    windH = (GLint)height;
+
+    glViewport(0, 0, (GLint)width, (GLint)height);
+    deltaY = windH /16;
+
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    gluOrtho2D(0, windW, 0, windH);
+    glMatrixMode(GL_MODELVIEW);
+}
+
+static void Key(unsigned char key, int x, int y)
+{
+
+    switch (key) {
+      case 27:
+	exit(1);
+      case 'd':
+	dithering = !dithering;
+	break;
+      default:
+	return;
+    }
+
+    glutPostRedisplay();
+}
+
+static void PrintColorStrings( void )
+{
+    GLubyte ubbuf[3];
+    int i, xleft, xright;
+    char colorString[18];
+
+    xleft = 5 + windW/4;
+    xright = 5 + windW/2;
+
+    for (i = windH - deltaY + 4; i > 0; i-=deltaY) {
+        glReadPixels(xleft, i+10, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, ubbuf);
+        sprintf(colorString, "(0x%x, 0x%x, 0x%x)",
+                ubbuf[0], ubbuf[1], ubbuf[2]);
+        glRasterPos2f(xleft, i);
+	DrawString(colorString);
+        glReadPixels(xright, i+10, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, ubbuf);
+        sprintf(colorString, "(0x%x, 0x%x, 0x%x)",
+                ubbuf[0], ubbuf[1], ubbuf[2]);
+        glRasterPos2f(xright, i);
+	DrawString(colorString);
+    }
+}
+
+static void Draw(void)
+{
+    int stringOffset = 5, stringx = 8;
+    int x1, x2, xleft, xright;
+    int i;
+
+    (dithering) ? glEnable(GL_DITHER) : glDisable(GL_DITHER);
+    glDisable(GL_BLEND);
+
+    glClearColor(0.5, 0.6, 0.1, 1.0);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    /* Draw background */
+    glColor3f(0.1, 0.1, 1.0);
+    glRectf(0.0, 0.0, windW/2, windH);
+
+    /* Draw labels */
+    glColor3f(0.8, 0.8, 0.0);
+    i = windH - deltaY + stringOffset;
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("SOURCE");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("DEST");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("min");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("max");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("subtract");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("reverse_subtract");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("clear");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("set");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("copy");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("noop");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("and");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("invert");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("or");
+    glRasterPos2f(stringx, i); i -= deltaY;
+    DrawString("xor");
+
+
+    i = windH - deltaY;
+    x1 = windW/4;
+    x2 = 3 * windW/4;
+    xleft = 5 + windW/4;
+    xright = 5 + windW/2;
+
+    /* Draw foreground color for comparison */
+    glColor3f(0.9, 0.2, 0.8);
+    glRectf(x1, i, x2, i+deltaY);
+
+    /* Leave one rectangle of background color */
+
+    /* Begin test cases */
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_ONE, GL_ONE);
+
+    i -= 2*deltaY;
+    glBlendEquationEXT(GL_MIN_EXT);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_MAX_EXT);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_FUNC_SUBTRACT_EXT);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_FUNC_REVERSE_SUBTRACT_EXT);
+    glRectf(x1, i, x2, i+deltaY);
+
+    glBlendFunc(GL_ONE, GL_ZERO);
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_CLEAR);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_SET);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_COPY);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_NOOP);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_AND);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_INVERT);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_OR);
+    glRectf(x1, i, x2, i+deltaY);
+
+    i -= deltaY;
+    glBlendEquationEXT(GL_LOGIC_OP);
+    glLogicOp(GL_XOR);
+    glRectf(x1, i, x2, i+deltaY);
+    glRectf(x1, i+10, x2, i+5);
+
+  if (doPrint) {
+      glDisable(GL_BLEND);
+      glColor3f(1.0, 1.0, 1.0);
+      PrintColorStrings();
+  }
+  glFlush();
+
+    if (doubleBuffer) {
+       glutSwapBuffers();
+    }
+
+}
+
+static GLenum Args(int argc, char **argv)
+{
+    GLint i;
+
+    doubleBuffer = GL_FALSE;
+
+    for (i = 1; i < argc; i++) {
+	if (strcmp(argv[i], "-sb") == 0) {
+	    doubleBuffer = GL_FALSE;
+	} else if (strcmp(argv[i], "-db") == 0) {
+	    doubleBuffer = GL_TRUE;
+	} else {
+	    printf("%s (Bad option).\n", argv[i]);
+	    return GL_FALSE;
+	}
+    }
+    return GL_TRUE;
+}
+
+int main(int argc, char **argv)
+{
+    GLenum type;
+    char *s;
+    char *extName1 = "GL_EXT_blend_logic_op";
+    char *extName2 = "GL_EXT_blend_minmax";
+    char *extName3 = "GL_EXT_blend_subtract";
+
+    glutInit(&argc, argv);
+
+    if (Args(argc, argv) == GL_FALSE) {
+	exit(1);
+    }
+
+    glutInitWindowPosition(0, 0); glutInitWindowSize( 800, 400);
+
+    type = GLUT_RGB;
+    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
+    glutInitDisplayMode(type);
+
+    if (glutCreateWindow("Blend Equation") == GL_FALSE) {
+	exit(1);
+    }
+
+    /* Make sure blend_logic_op extension is there. */
+    s = (char *) glGetString(GL_EXTENSIONS);
+    if (!s)
+	exit(1);
+    if (strstr(s,extName1) == 0) {
+	printf("Blend_logic_op extension is not present.\n");
+	exit(1);
+    }
+    if (strstr(s,extName2) == 0) {
+	printf("Blend_minmax extension is not present.\n");
+	exit(1);
+    }
+    if (strstr(s,extName3) == 0) {
+	printf("Blend_subtract extension is not present.\n");
+	exit(1);
+    }
+
+    Init();
+
+    glutReshapeFunc(Reshape);
+    glutKeyboardFunc(Key);
+    glutDisplayFunc(Draw);
+    glutMainLoop();
+    return 0;
+}