Rendering of a coordinate frame works

data/shaders/default_frag.glsl

@@ -5,5 +5,5 @@ smooth in vec4 ioFragColor;
 
 void main()
 {
-    fragColor = vec4(1.0, 0.0, 0.0, 1.0);
+    fragColor = ioFragColor;
 }

data/shaders/default_vert.glsl

@@ -15,5 +15,4 @@ void main()
 {
     ioFragColor = inColor;
     gl_Position = (uProjectionMatrix * uViewMatrix * uModelMatrix * inCoord);
-
 }

src/srender.c

@@ -55,8 +55,9 @@ typedef struct srmeshdata {
   int nvertices;
   int nindices;
 
-  GLuint vertex_buffer_id;
+  GLuint vao_id;
-  GLuint index_buffer_id;
+  GLuint vb_id;
+  GLuint idb_id;
 } srmeshdata;
 
 static srmeshdata gCoordFrameMesh = {0};
@@ -70,7 +71,8 @@ typedef struct srshader {
   GLuint frag_shader_id;
 } srshader;
 
-static srshader gDefaultShader = {"default_vert.glsl", "default_frag.glsl", 0, 0, 0};
+static srshader gDefaultShader =
+    {"default_vert.glsl", "default_frag.glsl", 0, 0, 0};
 
 bool srshader_compile(GLuint shader_id, const char* shader_src) {
   glShaderSource(shader_id, 1, &shader_src, 0);
@@ -94,7 +96,10 @@ bool srshader_compile (GLuint shader_id, const char* shader_src) {
   return true;
 }
 
-bool srshader_load (srshader* shader, const char* vert_src, const char* frag_src) {
+bool srshader_load(
+    srshader* shader,
+    const char* vert_src,
+    const char* frag_src) {
   shader->vert_shader_id = glCreateShader(GL_VERTEX_SHADER);
   if (!srshader_compile(shader->vert_shader_id, vert_src)) {
     gLog("Error compiling vertex shader!");
@@ -206,6 +211,49 @@ void init_shaders() {
 void init_debug_meshes() {
   assert(gCoordFrameMesh.nvertices == 0);
 
+  glGenVertexArrays(1, &gCoordFrameMesh.vao_id);
+  glBindVertexArray(gCoordFrameMesh.vao_id);
+
+  glGenBuffers(1, &gCoordFrameMesh.vb_id);
+  glBindBuffer(GL_ARRAY_BUFFER, gCoordFrameMesh.vb_id);
+
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(
+      0,
+      4,
+      GL_FLOAT,
+      GL_FALSE,
+      (sizeof(srvrtxdata)),
+      (void*)0);
+
+  glEnableVertexAttribArray(1);
+  glVertexAttribPointer(
+      1,
+      3,
+      GL_FLOAT,
+      GL_FALSE,
+      (sizeof(srvrtxdata)),
+      (void*)(sizeof(float) * 4));
+
+  // Attribute 2: texture coordinates
+  glEnableVertexAttribArray(2);
+  glVertexAttribPointer(
+      2,
+      2,
+      GL_FLOAT,
+      GL_FALSE,
+      (sizeof(srvrtxdata)),
+      (void*)(sizeof(float) * 7));
+  // Attribute 3: color
+  glEnableVertexAttribArray(3);
+  glVertexAttribPointer(
+      3,
+      4,
+      GL_UNSIGNED_BYTE,
+      GL_TRUE,
+      (sizeof(srvrtxdata)),
+      (void*)(sizeof(float) * 9));
+
   gCoordFrameMesh.nvertices = 6;
 
   srvrtxdata coord_frame_vertices[] = {
@@ -217,10 +265,8 @@ void init_debug_meshes() {
 
       {0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0, 0, 255, 255},
       {0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0, 0, 255, 255}};
-  GLuint coord_frame_indices[] = {0, 1, 1, 2, 3, 4};
+  GLuint coord_frame_indices[] = {0, 1, 2, 3, 4, 5};
 
-  glGenBuffers(1, &gCoordFrameMesh.vertex_buffer_id);
-  glBindBuffer(GL_ARRAY_BUFFER, gCoordFrameMesh.vertex_buffer_id);
   glBufferData(
       GL_ARRAY_BUFFER,
       sizeof(coord_frame_vertices),
@@ -228,14 +274,16 @@ void init_debug_meshes() {
       GL_STATIC_DRAW);
   glBindBuffer(GL_ARRAY_BUFFER, 0);
 
-  glGenBuffers(1, &gCoordFrameMesh.index_buffer_id);
+  glGenBuffers(1, &gCoordFrameMesh.idb_id);
-  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gCoordFrameMesh.index_buffer_id);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gCoordFrameMesh.idb_id);
   glBufferData(
       GL_ELEMENT_ARRAY_BUFFER,
       sizeof(coord_frame_indices),
       coord_frame_indices,
       GL_STATIC_DRAW);
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+  glBindVertexArray(0);
 };
 
 //
@@ -368,51 +416,13 @@ void srview_destroy(srview* sv) {
 }
 
 void srndr_run_frame_command(const srcmd* cmd) {
-  glBindBuffer(GL_ARRAY_BUFFER, gCoordFrameMesh.vertex_buffer_id);
+  glBindVertexArray(gCoordFrameMesh.vao_id);
 
-  glEnableVertexAttribArray(0);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gCoordFrameMesh.idb_id);
-  glVertexAttribPointer(
-      0,
-      4,
-      GL_FLOAT,
-      GL_FALSE,
-      (sizeof(srvrtxdata)),
-      (void*)0
-      );
-
-  glEnableVertexAttribArray(1);
-  glVertexAttribPointer(
-      1,
-      3,
-      GL_FLOAT,
-      GL_FALSE,
-      (sizeof(srvrtxdata)),
-      (void*)(sizeof(float) * 4)
-  );
-
-  // Attribute 2: texture coordinates
-  glEnableVertexAttribArray(2);
-  glVertexAttribPointer(
-      2,
-      2,
-      GL_FLOAT,
-      GL_FALSE,
-      (sizeof(srvrtxdata)),
-      (void*)(sizeof(float) * 7)
-  );
-  // Attribute 3: color
-  glEnableVertexAttribArray(3);
-  glVertexAttribPointer(
-      3,
-      4,
-      GL_UNSIGNED_BYTE,
-      GL_TRUE,
-      (sizeof(srvrtxdata)),
-      (void*)(sizeof(float) * 9)
-  );
-
-  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gCoordFrameMesh.index_buffer_id);
   glDrawElements(GL_LINES, 6, GL_UNSIGNED_INT, (void*)0);
+
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindVertexArray(0);
 }
 
 void srndr_render(srndr* srndr, srview* sview, srcmdbuf* scmdbuf) {
@@ -423,15 +433,18 @@ void srndr_render(srndr* srndr, srview* sview, srcmdbuf* scmdbuf) {
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
   glUseProgram(gDefaultShader.program_id);
-  GLint view_mat_loc = glGetUniformLocation(gDefaultShader.program_id, "uViewMatrix");
+  GLint view_mat_loc =
+      glGetUniformLocation(gDefaultShader.program_id, "uViewMatrix");
   assert(view_mat_loc != -1);
   glUniformMatrix4fv(view_mat_loc, 1, GL_FALSE, &sview->view);
 
-  GLint proj_mat_loc = glGetUniformLocation(gDefaultShader.program_id, "uProjectionMatrix");
+  GLint proj_mat_loc =
+      glGetUniformLocation(gDefaultShader.program_id, "uProjectionMatrix");
   assert(proj_mat_loc != -1);
   glUniformMatrix4fv(proj_mat_loc, 1, GL_FALSE, &sview->proj);
 
-  GLint model_mat_loc = glGetUniformLocation(gDefaultShader.program_id, "uModelMatrix");
+  GLint model_mat_loc =
+      glGetUniformLocation(gDefaultShader.program_id, "uModelMatrix");
   assert(model_mat_loc != -1);
 
   for (int i = 0; i < scmdbuf->ncmds; i++) {

src/vissim.cc

@@ -164,7 +164,7 @@ void DoRender() {
   srview_set_size(gView, content_avail.x, content_avail.y);
   simd4x4f view;
   simd4x4f proj;
-  simd4x4f_translation(&view, 0.1f, 0.1f, -0.1f);
+  simd4x4f_translation(&view, 0.1f, 0.1f, -0.5f);
   simd4x4f_lookat(
       &view,
       simd4f_create(1.f, 1.f, 1.f, 1.f),