Databases
StackOverflow2013
Postsdbo
POOpenGL VBO Drawing
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POOpenGL VBO Drawing
    primarykey
    data
    text
    <p>I seem to be having some trouble drawing objects in OpenGL using VBOs. I've attempted to copy the example from: <a href="http://www.opengl.org/wiki/VBO_-_just_examples" rel="nofollow">http://www.opengl.org/wiki/VBO_-_just_examples</a> (number 2) but I can't get a plane to appear on screen.</p> <p>Vertex.h:</p> <pre><code>#include &lt;freeglut&gt; struct Vertex { GLfloat position[3]; GLfloat normal[3]; GLfloat *uvs[2]; unsigned short uvCount; }; </code></pre> <p>Triangles.h:</p> <pre><code>#include &lt;GL/glew.h&gt; #include "Vertex.h" class Triangles { public: Triangles(GLuint program, Vertex *vertices, unsigned int vertexCount, unsigned int *indices[3], unsigned int indiceCount); ~Triangles(); void Draw(); private: GLuint program; GLuint VertexVBOID; GLuint IndexVBOID; GLuint VaoID; unsigned int *indices[3]; unsigned int indiceCount; }; </code></pre> <p>Triangles.cpp:</p> <pre><code>#include "Triangles.h" #include &lt;stdio.h&gt; #include &lt;stddef.h&gt; Triangles::Triangles(GLuint program, unsigned int *indices[3], unsigned int indiceCount) { memcpy(this-&gt;indices, indices, sizeof(int) * indiceCount * 3); this-&gt;indiceCount = indiceCount; this-&gt;program = program; glGenVertexArrays(1, &amp;VaoID); glBindVertexArray(VaoID); glGenBuffers(1, &amp;VertexVBOID); glBindBuffer(GL_ARRAY_BUFFER, VertexVBOID); glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * vertexCount, vertices, GL_STATIC_DRAW); GLuint attributeLocation = glGetAttribLocation(program, "position"); glEnableVertexAttribArray(attributeLocation); glVertexAttribPointer(attributeLocation, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid *)(offsetof(Vertex, position))); attributeLocation = glGetAttribLocation(program, "normal"); glEnableVertexAttribArray(attributeLocation); glVertexAttribPointer(attributeLocation, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid *)(offsetof(Vertex, normal))); glGenBuffers(1, &amp;IndexVBOID); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IndexVBOID); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(unsigned int) * 3 * indiceCount, indices, GL_STATIC_DRAW); }; Triangles::~Triangles() { glDisableVertexAttribArray(glGetAttribLocation(program, "position")); glDisableVertexAttribArray(glGetAttribLocation(program, "normal")); glDeleteBuffers(1, &amp;VertexVBOID); glDeleteBuffers(1, &amp;IndexVBOID); glDeleteVertexArrays(1, &amp;VaoID); } void Triangles::Draw() { glBindVertexArray(VaoID); glDrawElements(GL_TRIANGLES, indiceCount, GL_UNSIGNED_INT, 0); }; </code></pre> <p>Excerpt from main.cpp (creating triagle object):</p> <pre><code>Vertex vertices[4]; vertices[0].position[0] = -1; vertices[0].position[1] = 1; vertices[0].position[2] = 0; vertices[0].normal[0] = 0; vertices[0].normal[0] = 0; vertices[0].normal[0] = 1; vertices[0].uvCount = 0; vertices[1].position[0] = 1; vertices[1].position[1] = 1; vertices[1].position[2] = 0; vertices[1].normal[0] = 0; vertices[1].normal[0] = 0; vertices[1].normal[0] = 1; vertices[1].uvCount = 0; vertices[2].position[0] = 1; vertices[2].position[1] = -1; vertices[2].position[2] = 0; vertices[2].normal[0] = 0; vertices[2].normal[0] = 0; vertices[2].normal[0] = 1; vertices[2].uvCount = 0; vertices[3].position[0] = -1; vertices[3].position[1] = -1; vertices[3].position[2] = 0; vertices[3].normal[0] = 0; vertices[3].normal[0] = 0; vertices[3].normal[0] = 1; vertices[3].uvCount = 0; unsigned int **indices; indices = new unsigned int*[2]; indices[0] = new unsigned int[3]; indices[0][0] = 0; indices[0][1] = 1; indices[0][2] = 2; indices[1] = new unsigned int[3]; indices[1][0] = 2; indices[1][1] = 3; indices[1][2] = 0; Triangles *t = new Triangles(program, vertices, 4 indices, 2); </code></pre> <p>createShader(GLenum , char *):</p> <pre><code>GLuint createShader(GLenum type, char *file) { GLuint shader = glCreateShader(type); const char *fileData = textFileRead(file); glShaderSource(shader, 1, &amp;fileData, NULL); glCompileShader(shader); return shader; } </code></pre> <p>Shader loading:</p> <pre><code> GLuint v = createShader(GL_VERTEX_SHADER); GLuint f = createShader(GL_FRAGMENT_SHADER, "fragmentShader.frag"); program = glCreateProgram(); glAttachShader(program, v); glAttachShader(program, f); glLinkProgram(program); glUseProgram(program); </code></pre> <p>vertexShader.vert:</p> <pre><code>in vec3 position; in vec3 normal; out vec3 a_normal; void main() { gl_Position = vec4(position, 1.0); } </code></pre> <p>fragmentShader.frag:</p> <pre><code>in vec3 a_normal; out vec4 out_color; void main() { out_color = vec4(1.0, 1.0, 1.0, 1.0); } </code></pre> <p>Please let me know if more code is needed. As a side note everything compiles just fine, I just don't see the plane that I have constructed on screen (maybe because I didn't use colors?)</p> <p>My OpenGL information is as follows:</p> <ul> <li>Vendor: ATI Technologies Inc.</li> <li>Renderer: ATI Radeon HD 5700 Series</li> <li>Version: 3.2.9756 Compatibility Profile Context</li> <li>Extensions: extensions = GL_AMDX_name_gen_delete GL_AMDX_random_access_target GL_AMDX_vertex_shader_tessellator GL_AMD_conservative_depth GL_AMD_draw_buffers_blend GL_AMD_performance_monitor GL_AMD_seamless_cubemap_per_texture GL_AMD_shader_stencil_export GL_AMD_texture</li> </ul>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USBenjamin Danger Johnson
    1. USBenjamin Danger Johnson
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. COSome notes, in no particular order: Do you do error checking (`glGetError`)? Where is modelviewproj set? Why are you using glRotate/Translate/PopMatrix if you're using a custom mvp matrix? Are you certain your attribute indices are `0` and `1`?
      singulars
      1. POOpenGL VBO Drawing
      1. USTim
    2. COUnfortunately I do not do error checking, I mainly just copied the example and I am trying to run its code. I used matrix functions because I didn't realize the vertex shader would effect that. I assumed the matrix set to the matrix at the top of the stack (the one I pushed before drawing.) As for indices, I'm not exactly sure what you mean. I just drew the vertices on paper and decided the indices based on that. Unless you mean the normal and position values in glEnableVertexArrayAttrib(), I just used the values in the example, I'm not sure how to change them or what they effect.
      singulars
      1. POOpenGL VBO Drawing
      1. USBenjamin Danger Johnson
    3. COIn my project I also draw a cube (using glBegin and glEnd) as a test, and it seems it dissapears when the shaders are active and working. Could this be a sign of a shader problem? if it is, does anyone know how I can fix it?
      singulars
      1. POOpenGL VBO Drawing
      1. USBenjamin Danger Johnson
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload