1 #define GL_GLEXT_PROTOTYPES 1
10 #define HSV_WHEEL_SIZE 128
14 void draw_hsv_wheel(float y, float rad, float theta, float value)
18 glActiveTexture(GL_TEXTURE0);
20 glEnable(GL_TEXTURE_2D);
22 glBindTexture(GL_TEXTURE_2D, hsv_wheel_num);
24 glActiveTexture(GL_TEXTURE1);
26 glBindTexture(GL_TEXTURE_2D, 0);
28 glActiveTexture(GL_TEXTURE0);
31 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
37 glTexCoord2f(0.0f, 1.0f);
40 glTexCoord2f(1.0f, 1.0f);
41 glVertex2f(0.2f * 9.0f / 16.0f, y);
43 glTexCoord2f(1.0f, 0.0f);
44 glVertex2f(0.2f * 9.0f / 16.0f, y + 0.2f);
46 glTexCoord2f(0.0f, 0.0f);
47 glVertex2f(0.0f, y + 0.2f);
52 glDisable(GL_TEXTURE_2D);
53 glColor3f(0.0f, 0.0f, 0.0f);
56 glVertex2f((0.1f + rad * cos(theta) * 0.1f) * 9.0f / 16.0f, y + 0.1f - rad * sin(theta) * 0.1f);
60 glDisable(GL_TEXTURE_2D);
63 glColor3f(0.0f, 0.0f, 0.0f);
64 glVertex2f(0.22f * 9.0f / 16.0f, y);
65 glVertex2f(0.24f * 9.0f / 16.0f, y);
67 glColor3f(1.0f, 1.0f, 1.0f);
68 glVertex2f(0.24f * 9.0f / 16.0f, y + 0.2f);
69 glVertex2f(0.22f * 9.0f / 16.0f, y + 0.2f);
74 glColor3f(0.0f, 0.0f, 0.0f);
77 glVertex2f(0.23f * 9.0f / 16.0f, y + value * 0.2f);
80 glColor3f(1.0f, 1.0f, 1.0f);
83 void draw_saturation_bar(float y, float saturation)
89 glDisable(GL_TEXTURE_2D);
92 glColor3f(0.0f, 0.0f, 0.0f);
93 glVertex2f(0.0f * 9.0f / 16.0f, y + 0.02f);
94 glVertex2f(0.0f * 9.0f / 16.0f, y);
96 glColor3f(1.0f, 1.0f, 1.0f);
97 glVertex2f(0.2f * 9.0f / 16.0f, y);
98 glVertex2f(0.2f * 9.0f / 16.0f, y + 0.02f);
103 glColor3f(0.0f, 0.0f, 0.0f);
106 glVertex2f(0.2f * saturation * 9.0f / 16.0f, y + 0.01f);
109 glColor3f(1.0f, 1.0f, 1.0f);
112 void make_hsv_wheel_texture()
114 glGenTextures(1, &hsv_wheel_num);
116 static unsigned char hsv_pix[HSV_WHEEL_SIZE * HSV_WHEEL_SIZE * 4];
117 for (int y = 0; y < HSV_WHEEL_SIZE; ++y) {
118 for (int x = 0; x < HSV_WHEEL_SIZE; ++x) {
119 float yf = 2.0f * y / (float)(HSV_WHEEL_SIZE) - 1.0f;
120 float xf = 2.0f * x / (float)(HSV_WHEEL_SIZE) - 1.0f;
121 float rad = hypot(xf, yf);
122 float theta = atan2(yf, xf);
125 hsv2rgb(theta, rad, 1.0f, &r, &g, &b);
126 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 0] = lrintf(r * 255.0f);
127 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 1] = lrintf(g * 255.0f);
128 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 2] = lrintf(b * 255.0f);
131 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 0;
133 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 255;
139 glBindTexture(GL_TEXTURE_2D, hsv_wheel_num);
141 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
143 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, HSV_WHEEL_SIZE, HSV_WHEEL_SIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, hsv_pix);
147 void read_colorwheel(float xf, float yf, float *rad, float *theta, float *value)
149 if (xf < 0.2f && yf < 0.2f) {
150 float xp = 2.0f * xf / 0.2f - 1.0f;
151 float yp = -(2.0f * yf / 0.2f - 1.0f);
152 *rad = hypot(xp, yp);
153 *theta = atan2(yp, xp);
157 } else if (xf >= 0.22f && xf <= 0.24f) {