--- /dev/null
+/**
+ * Test XOR emulation with blending.
+ *
+ */
+
+#define GL_GLEXT_PROTOTYPES
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glut.h>
+#include "readtex.c"
+
+#define IMAGE_FILE "../images/arch.rgb"
+
+static int ImgWidth, ImgHeight;
+static GLenum ImgFormat;
+static GLubyte *Image = NULL;
+
+static int Win;
+static int Width = 600, Height = 600;
+
+struct rect
+{
+ int x0, y0, x1, y1;
+};
+
+static struct rect OldRect, NewRect;
+
+static GLboolean ButtonDown = GL_FALSE;
+static GLboolean LogicOp = 0*GL_TRUE;
+
+
+static const GLfloat red[4] = {1.0, 0.2, 0.2, 1.0};
+static const GLfloat green[4] = {0.2, 1.0, 0.2, 1.0};
+static const GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0};
+
+
+static void
+PrintString(const char *s)
+{
+ while (*s) {
+ glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+ s++;
+ }
+}
+
+
+static void
+Draw(void)
+{
+ glClear(GL_COLOR_BUFFER_BIT);
+
+ glWindowPos2i((Width - ImgWidth) / 2, (Height - ImgHeight) / 2);
+ glDrawPixels(ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image);
+
+ /*
+ * Draw 2D XOR rects
+ */
+ glColor3f(1, 1, 1);
+
+ glWindowPos2i(100, Height - 20);
+ PrintString("XOR LogicOp:");
+ glLogicOp(GL_XOR);
+ glEnable(GL_COLOR_LOGIC_OP);
+ glRecti(100, 30, 250, Height - 30);
+ glDisable(GL_COLOR_LOGIC_OP);
+
+ glWindowPos2i(Width/2 + 10, Height - 20);
+ PrintString("Invert Blending:");
+ glBlendFunc(GL_ONE, GL_ONE);
+ glBlendEquation(GL_FUNC_SUBTRACT);
+ glEnable(GL_BLEND);
+ glRecti(Width / 2, 30, Width / 2 + 150, Height - 30);
+ glDisable(GL_BLEND);
+
+ glutSwapBuffers();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+ Width = width;
+ Height = height;
+ glViewport(0, 0, width, height);
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0, Width, 0, Height, -1, 1);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case 'b':
+ case 'B':
+ LogicOp = GL_FALSE;
+ break;
+ case 'l':
+ case 'L':
+ LogicOp = GL_TRUE;
+ break;
+ case 27:
+ glutDestroyWindow(Win);
+ exit(0);
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case GLUT_KEY_UP:
+ break;
+ case GLUT_KEY_DOWN:
+ break;
+ case GLUT_KEY_LEFT:
+ break;
+ case GLUT_KEY_RIGHT:
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+static void
+MouseMotion(int x, int y)
+{
+ if (ButtonDown) {
+ NewRect.x1 = x;
+ NewRect.y1 = y;
+ glutPostRedisplay();
+ }
+}
+
+
+static void
+MouseButton(int button, int state, int x, int y)
+{
+ if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
+ ButtonDown = GL_TRUE;
+ NewRect.x0 = NewRect.x1 = x;
+ NewRect.y0 = NewRect.y1 = y;
+ OldRect = NewRect;
+ }
+ else if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
+ ButtonDown = GL_FALSE;
+ }
+}
+
+
+static void
+Init(void)
+{
+ /*
+ * Load image and scale if needed.
+ */
+ Image = LoadRGBImage(IMAGE_FILE, &ImgWidth, &ImgHeight, &ImgFormat);
+ if (!Image) {
+ printf("Couldn't read %s\n", IMAGE_FILE);
+ exit(0);
+ }
+
+ glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+ glPixelStorei(GL_PACK_ALIGNMENT, 1);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ glutInit(&argc, argv);
+ glutInitWindowSize(Width, Height);
+ glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
+ Win = glutCreateWindow(argv[0]);
+ glutReshapeFunc(Reshape);
+ glutKeyboardFunc(Key);
+ glutSpecialFunc(SpecialKey);
+ glutMotionFunc(MouseMotion);
+ glutMouseFunc(MouseButton);
+ glutDisplayFunc(Draw);
+ Init();
+ glutPostRedisplay();
+ glutMainLoop();
+ return 0;
+}
--- /dev/null
+/**
+ * Test rubber-band selection box w/ logicops and blend.
+ */
+
+#define GL_GLEXT_PROTOTYPES
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glut.h>
+#include "readtex.c"
+
+#define IMAGE_FILE "../images/arch.rgb"
+
+static int ImgWidth, ImgHeight;
+static GLenum ImgFormat;
+static GLubyte *Image = NULL;
+
+static int Win;
+static int Width = 512, Height = 512;
+
+struct rect
+{
+ int x0, y0, x1, y1;
+};
+
+static struct rect OldRect, NewRect;
+
+static GLboolean ButtonDown = GL_FALSE;
+static GLboolean LogicOp = 0*GL_TRUE;
+
+static GLboolean RedrawBackground = GL_TRUE;
+
+static const GLfloat red[4] = {1.0, 0.2, 0.2, 1.0};
+static const GLfloat green[4] = {0.2, 1.0, 0.2, 1.0};
+static const GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0};
+
+
+/*
+ * Draw rubberband box in front buffer
+ */
+static void
+DrawRect(const struct rect *r)
+{
+ glDrawBuffer(GL_FRONT);
+
+ if (LogicOp) {
+ glLogicOp(GL_XOR);
+ glEnable(GL_COLOR_LOGIC_OP);
+ }
+ else {
+ glEnable(GL_BLEND);
+ glBlendFunc(GL_ONE, GL_ONE);
+ glBlendEquation(GL_FUNC_SUBTRACT);
+ }
+
+ glColor3f(1, 1, 1);
+
+ glLineWidth(3.0);
+
+ glBegin(GL_LINE_LOOP);
+ glVertex2i(r->x0, r->y0);
+ glVertex2i(r->x1, r->y0);
+ glVertex2i(r->x1, r->y1);
+ glVertex2i(r->x0, r->y1);
+ glEnd();
+
+ glDisable(GL_COLOR_LOGIC_OP);
+ glDisable(GL_BLEND);
+
+ glDrawBuffer(GL_BACK);
+}
+
+
+static void
+PrintString(const char *s)
+{
+ while (*s) {
+ glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+ s++;
+ }
+}
+
+
+static void
+DrawBackground(void)
+{
+ char s[100];
+
+ sprintf(s, "[L/B] %s mode. Use mouse to make selection box.",
+ LogicOp ? "LogicOp" : "Blend");
+
+ glClear(GL_COLOR_BUFFER_BIT);
+
+ glWindowPos2i((Width - ImgWidth) / 2, (Height - ImgHeight) / 2);
+ glDrawPixels(ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image);
+
+ glWindowPos2i(10, 10);
+ PrintString(s);
+
+ glutSwapBuffers();
+}
+
+
+static void
+Draw(void)
+{
+ if (RedrawBackground) {
+ DrawBackground();
+ }
+
+ if (ButtonDown) {
+ if (!RedrawBackground)
+ DrawRect(&OldRect); /* erase old */
+
+ DrawRect(&NewRect); /* draw new */
+
+ OldRect = NewRect;
+ }
+
+ RedrawBackground = GL_FALSE;
+}
+
+
+static void
+Reshape(int width, int height)
+{
+ Width = width;
+ Height = height;
+
+ glViewport(0, 0, width, height);
+
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0, Width, Height, 0, -1, 1); /* Inverted Y! */
+
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+
+ RedrawBackground = GL_TRUE;
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case 'b':
+ case 'B':
+ LogicOp = GL_FALSE;
+ break;
+ case 'l':
+ case 'L':
+ LogicOp = GL_TRUE;
+ break;
+ case 27:
+ glutDestroyWindow(Win);
+ exit(0);
+ break;
+ }
+ RedrawBackground = GL_TRUE;
+ glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case GLUT_KEY_UP:
+ break;
+ case GLUT_KEY_DOWN:
+ break;
+ case GLUT_KEY_LEFT:
+ break;
+ case GLUT_KEY_RIGHT:
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+static void
+MouseMotion(int x, int y)
+{
+ if (ButtonDown) {
+ NewRect.x1 = x;
+ NewRect.y1 = y;
+ glutPostRedisplay();
+ }
+}
+
+
+static void
+MouseButton(int button, int state, int x, int y)
+{
+ if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
+ ButtonDown = GL_TRUE;
+ RedrawBackground = GL_TRUE;
+ NewRect.x0 = NewRect.x1 = x;
+ NewRect.y0 = NewRect.y1 = y;
+ OldRect = NewRect;
+ }
+ else if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
+ ButtonDown = GL_FALSE;
+ }
+ glutPostRedisplay();
+}
+
+
+static void
+Init(void)
+{
+ Image = LoadRGBImage(IMAGE_FILE, &ImgWidth, &ImgHeight, &ImgFormat);
+ if (!Image) {
+ printf("Couldn't read %s\n", IMAGE_FILE);
+ exit(0);
+ }
+
+ glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+ glPixelStorei(GL_PACK_ALIGNMENT, 1);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ glutInit(&argc, argv);
+ glutInitWindowSize(Width, Height);
+ glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
+ Win = glutCreateWindow(argv[0]);
+ glutReshapeFunc(Reshape);
+ glutKeyboardFunc(Key);
+ glutSpecialFunc(SpecialKey);
+ glutMotionFunc(MouseMotion);
+ glutMouseFunc(MouseButton);
+ glutDisplayFunc(Draw);
+ Init();
+ glutPostRedisplay();
+ glutMainLoop();
+ return 0;
+}