opengl_x11

commit 178b30516d7089192ab60973d7b2ab5a2edea450
parent 2e3cf4e48f6aec3834e75675b2fd7847beabdc3b
Author: bsandro <email@bsandro.tech>
Date:   Mon,  1 Dec 2025 01:40:46 +0200

crawling square (changing vertex buffer every frame)

Diffstat:
M
obj2d.c
 | 
27
++++++++++++++++++---------

1 file changed, 18 insertions(+), 9 deletions(-)
diff --git a/obj2d.c b/obj2d.c
@@ -12,6 +12,9 @@
 #include <GL/glx.h>
 #include <GL/glu.h>
 
+#define SIZE_W 800
+#define SIZE_H 800
+
 #define LEN(x) (sizeof(x)/sizeof(x[0]))
 
 #define GL_CHECK(x)                                                                           \
@@ -32,11 +35,10 @@ static const double current_ts() {
 
 static double t_started;
 
-//@todo move shaders to separate files
 static const GLchar *vertexSrc = R"(
 #version 420
-layout(location=0) in vec2 position;
-layout(location=1) in vec3 color;
+in vec2 position;
+in vec3 color;
 out vec3 dotColor;
 void main() {
     gl_Position = vec4(position, 0.0, 1.0);
@@ -73,7 +75,11 @@ uniform double iTime;
 in vec3 fColor;
 out vec4 outColor;
 void main() {
-    outColor = vec4(fColor, 1.0);
+    vec3 color = fColor;
+    if  (gl_FragCoord.x < 300) {
+        color.g = 1.0f;
+    }
+    outColor = vec4(color, 1.0);
 }
 )";
 
@@ -96,8 +102,8 @@ static GLuint linkProgram(GLuint vertex, GLuint geometry, GLuint fragment) {
     glAttachShader(shaderProgram, vertex);
     glAttachShader(shaderProgram, geometry);
     glAttachShader(shaderProgram, fragment);
-    glBindAttribLocation(shaderProgram, 0, "position");
-    glBindAttribLocation(shaderProgram, 1, "color");
+    //glBindAttribLocation(shaderProgram, 0, "position");
+    //glBindAttribLocation(shaderProgram, 1, "color");
     glLinkProgram(shaderProgram);
     return shaderProgram;
 }
@@ -136,7 +142,7 @@ int main(int argc, char *argv[]) {
     Colormap cmap = XCreateColormap(dpy, root, vi->visual, AllocNone);
     swa.colormap = cmap;
     swa.event_mask = ExposureMask | KeyPressMask;
-    win = XCreateWindow(dpy, root, 0, 0, 500, 500, 0, vi->depth, InputOutput, vi->visual, CWColormap | CWEventMask, &swa);
+    win = XCreateWindow(dpy, root, 0, 0, SIZE_W, SIZE_H, 0, vi->depth, InputOutput, vi->visual, CWColormap | CWEventMask, &swa);
     XMapWindow(dpy, win);
     XStoreName(dpy, win, "OPENGL");
     GLXContext ctx = glXCreateContext(dpy, vi, NULL, GL_TRUE);
@@ -156,7 +162,7 @@ int main(int argc, char *argv[]) {
     glBindVertexArray(vao);
 
     // x,y, color(r,g,b)
-    static const GLfloat vertices[][5] = {
+    GLfloat vertices[][5] = {
         {-0.3, -0.5, 1.f, 0.f, 0.f},
         { 0.6, -0.1, 0.f, 1.f, 0.f},
         { 0.4,  0.4, 0.f, 0.f, 1.f},
@@ -166,7 +172,7 @@ int main(int argc, char *argv[]) {
     GLuint vbo;
     glGenBuffers(1, &vbo);
     glBindBuffer(GL_ARRAY_BUFFER, vbo);
-    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_DYNAMIC_DRAW);
 
     GLuint vertex = mkShader(GL_VERTEX_SHADER, vertexSrc);
     GLuint geometry = mkShader(GL_GEOMETRY_SHADER, geometrySrc);
@@ -208,6 +214,9 @@ int main(int argc, char *argv[]) {
                 glViewport(0, 0, ce->width, ce->height);
             }
         }
+vertices[0][0] += 0.0003f;
+glNamedBufferData(vbo, sizeof(vertices), vertices, GL_DYNAMIC_DRAW);
+
 
         glClearColor(0.1f, 0.1f, 0.15f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT);