commit 6e83362402a67dc708acc6fddcc2771af9cce4d7
parent e3e8705316acdc30fb75835207d448d276e9400e
Author: bsandro <email@bsandro.tech>
Date: Mon, 20 Oct 2025 22:19:01 +0300
resurrected wrongly moved file
Diffstat:
| M | shaders.c | | | 149 | +++++++++++++++++++++++++++++-------------------------------------------------- |
1 file changed, 55 insertions(+), 94 deletions(-)
diff --git a/shaders.c b/shaders.c
@@ -1,4 +1,4 @@
-/* tesselation */
+/* basic vertex+fragment shaders */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -12,9 +12,14 @@
#include <GL/glx.h>
#include <GL/glu.h>
-#ifndef CALLBACK
-#define CALLBACK void (*)(void)
-#endif
+Display *dpy;
+Window root;
+GLint att[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
+XVisualInfo *vi;
+XSetWindowAttributes swa;
+Window win;
+XWindowAttributes gwa;
+XEvent xev;
static const double current_ts() {
struct timespec ts;
@@ -24,41 +29,6 @@ static const double current_ts() {
static double t_started;
-static void tessCbBegin(GLenum type) {
- glBegin(type);
- printf("glBegin(%d)\n", type);
-}
-
-static void tessCbVertex(void *data) {
- const float scale = 0.2f;
- const GLdouble *p = data;
- glVertex3d(p[0]*scale, p[1]*scale, p[2]);
- printf("glVertex3d(%.1f, %.1f, %.1f)\n", *p, *(p+1), *(p+2));
-}
-
-static void tessCbEnd() {
- glEnd();
- printf("glEnd()\n");
-}
-
-static void tessCbError(GLenum errno) {
- printf("tesselator error: %d\n", errno);
-}
-
-static void tessCbCombine(GLdouble coords[3], GLdouble *data[4], GLfloat weight[4], void **outData) {
- // let memory leak for now
- GLdouble *out = malloc(sizeof(GLdouble)*7); // x,y,z,r,g,b,a
- out[0] = coords[0];
- out[1] = coords[1];
- out[2] = coords[2];
- // color
- out[3] = weight[0]*data[0][3]+weight[1]*data[1][3]+weight[2]*data[2][3]+weight[3]*data[3][3];
- out[4] = weight[0]*data[0][4]+weight[1]*data[1][4]+weight[2]*data[2][4]+weight[3]*data[3][4];
- out[5] = weight[0]*data[0][5]+weight[1]*data[1][5]+weight[2]*data[2][5]+weight[3]*data[3][5];
- out[6] = weight[0]*data[0][6]+weight[1]*data[1][6]+weight[2]*data[2][6]+weight[3]*data[3][6];
- *outData = out;
-}
-
//@todo move shaders to separate files
static const GLchar *vertexSrc = " \n\
#version 420 \n\
@@ -117,20 +87,15 @@ void __attribute((destructor)) end() {
}
int main(int argc, char *argv[]) {
- Display *dpy = XOpenDisplay(NULL);
- XSetWindowAttributes swa;
- Window win;
- XWindowAttributes gwa;
- XEvent xev;
- GLint attr[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
+ dpy = XOpenDisplay(NULL);
if (dpy == NULL) {
printf("\n\tcannot connect to X server\n\n");
exit(0);
}
- Window root = DefaultRootWindow(dpy);
- XVisualInfo *vi = glXChooseVisual(dpy, 0, attr);
+ root = DefaultRootWindow(dpy);
+ vi = glXChooseVisual(dpy, 0, att);
if (vi == NULL) {
printf("\n\tno appropriate visual found\n\n");
@@ -148,29 +113,42 @@ int main(int argc, char *argv[]) {
GLXContext ctx = glXCreateContext(dpy, vi, NULL, GL_TRUE);
glXMakeCurrent(dpy, win, ctx);
- //GLdouble vertices_poly[][3] = { {-2,3,0}, {-2,0,0}, {2,0,0}, { 2,3,0}, {-1,2,0}, {-1,1,0}, {1,1,0}, { 1,2,0} };
- //GLdouble vertices_poly[][3] = { {-1,2,0}, {0,0,0}, {1,2,0}, {0,1.5,0} };
- /*GLdouble vertices_poly[][3] = {
- { -0.7, -0.5, 0.0 },
- { -0.3, 0.3, 0.0 },
- { 0.0, 0.6, 0.0 },
- { 0.4, 0.3, 0.0 },
- { 0.2, -0.4, 0.0 },
- { 0.7, -0.4, 0.0 },
- { -0.4, -0.7, 0.0 }
- };*/
- GLdouble vertices_poly[][6] = { { 0.0, 3.0, 0, 1, 0, 0},
- {-1.0, 0.0, 0, 0, 1, 0},
- { 1.6, 1.9, 0, 1, 0, 1},
- {-1.6, 1.9, 0, 1, 1, 0},
- { 1.0, 0.0, 0, 0, 0, 1} };
- int vertices_num = sizeof(vertices_poly)/sizeof(vertices_poly[0]);
- GLUtesselator *tess = gluNewTess();
- gluTessCallback(tess, GLU_TESS_BEGIN, (CALLBACK)tessCbBegin);
- gluTessCallback(tess, GLU_TESS_END, (CALLBACK)tessCbEnd);
- gluTessCallback(tess, GLU_TESS_VERTEX, (CALLBACK)tessCbVertex);
- gluTessCallback(tess, GLU_TESS_ERROR, (CALLBACK)tessCbError);
- gluTessCallback(tess, GLU_TESS_COMBINE, (CALLBACK)tessCbCombine);
+ GLuint vao;
+ glGenVertexArrays(1, &vao);
+ glBindVertexArray(vao);
+
+ // [x, y, r, g, b]
+ static const GLfloat vertices[] = {
+ 0.01f, 0.01f, 1.0f, 0.0f, 0.0f,
+ 0.8f, 0.0f, 0.0f, 1.0f, 0.0f,
+ 0.0f, 0.8f, 0.0f, 0.0f, 1.0f,
+
+ -0.01f, -0.01f, 0.0f, 0.0f, 1.0f,
+ -0.8f, 0.0f, 0.0f, 1.0f, 0.0f,
+ 0.0f, -0.8f, 1.0f, 0.0f, 0.0f,
+
+ 0.3f, 0.3f, 1.0f, 0.0f, 0.0f,
+ 0.3f, 0.6f, 1.0f, 0.0f, 0.0f,
+ 0.6f, 0.3f, 1.0f, 0.0f, 0.0f,
+ 0.6f, 0.6f, 1.0f, 0.0f, 0.0f
+ };
+
+ static const GLuint elements[] = {
+ 0, 1, 5,
+ 3, 2, 4,
+ 6, 7, 8,
+ 7, 8, 9
+ };
+
+ GLuint vbo;
+ glGenBuffers(1, &vbo);
+ glBindBuffer(GL_ARRAY_BUFFER, vbo);
+ glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+ GLuint ebo;
+ glGenBuffers(1, &ebo);
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
+ glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(elements), elements, GL_STATIC_DRAW);
GLuint vertex = mkShader(GL_VERTEX_SHADER, vertexSrc);
GLuint fragment = mkShader(GL_FRAGMENT_SHADER, fragmentSrc);
@@ -198,18 +176,6 @@ int main(int argc, char *argv[]) {
}
}
- // this scaling doesn't work for tesselation !!!
-
- /*glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
- glOrtho(-10, 10, -10, 10, -1.5, 1.5);
- glMatrixMode(GL_MODELVIEW);
- glLoadIdentity();*/
-
- //glMatrixMode(GL_MODELVIEW);
- //glLoadIdentity();
- //glScaled(0.1, 0.1, 1.0);
-
glClearColor(0.1f, 0.1f, 0.15f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
@@ -219,18 +185,13 @@ int main(int argc, char *argv[]) {
glUseProgram(shaderPrg);
- GLuint list = glGenLists(1);
- glNewList(list, GL_COMPILE);
- gluTessBeginPolygon(tess, NULL);
- gluTessBeginContour(tess);
- for (int i=0;i<vertices_num;++i) {
- gluTessVertex(tess, vertices_poly[i], vertices_poly[i]);
- }
- gluTessEndContour(tess);
- gluTessEndPolygon(tess);
- glEndList();
-
- glCallList(list);
+ GLint position = glGetAttribLocation(shaderPrg, "position");
+ glEnableVertexAttribArray(position);
+ glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 5*sizeof(GLfloat), 0);
+ GLint color = glGetAttribLocation(shaderPrg, "inColor");
+ glEnableVertexAttribArray(color);
+ glVertexAttribPointer(color, 3, GL_FLOAT, GL_FALSE, 5*sizeof(GLfloat), (void *)(2*sizeof(GLfloat)));
+ glDrawElements(GL_TRIANGLES, sizeof(elements), GL_UNSIGNED_INT, 0);
glXSwapBuffers(dpy, win);
usleep(1000*16);
