blob: 866a0f519e50aa513f909af68b26c288942d2696 [file] [log] [blame]
/**
* Test rubber-band selection box w/ logicops and blend.
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glew.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]);
glewInit();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutSpecialFunc(SpecialKey);
glutMotionFunc(MouseMotion);
glutMouseFunc(MouseButton);
glutDisplayFunc(Draw);
Init();
glutPostRedisplay();
glutMainLoop();
return 0;
}