[英]glDrawElements not drawing
我使用以下代碼創建緩沖區:
//generate buffers
glGenVertexArrays(1, &VAO);
//glGenBuffers(1, &EBO);
glGenBuffers(1, &VBO_vertices);
glGenBuffers(1, &VBO_colors);
glGenBuffers(1, &VBO_normals);
// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
glBindVertexArray(VAO);
// Copy our vertices array in a buffer for OpenGL to use
glBindBuffer(GL_ARRAY_BUFFER, VBO_vertices);
glBufferData(GL_ARRAY_BUFFER, sizeof(float)*3*vertices.size(), &vertices[0], GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, vTable.size() * sizeof(int), &vTable[0], GL_STATIC_DRAW);
// Position attribute
glVertexAttribPointer((GLuint)0, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid*)0); //size = 3 (X,Y,Z)
glEnableVertexAttribArray(0);
//Buffer for color
glBindBuffer(GL_ARRAY_BUFFER, VBO_colors);
glBufferData(GL_ARRAY_BUFFER, sizeof(float)*3*vertices.size(), &v_color[0], GL_STATIC_DRAW);
// Color attribute
glVertexAttribPointer((GLuint)1, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid*)0); //size = 3 (R,G,B)
glEnableVertexAttribArray(1);
//Buffer for normals
glBindBuffer(GL_ARRAY_BUFFER, VBO_normals);
glBufferData(GL_ARRAY_BUFFER, sizeof(float)*3*vertices.size(), &v_normals[0], GL_STATIC_DRAW);
//normal attribute
glVertexAttribPointer((GLuint)2, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid*)0); //size = 3 (R,G,B)
glEnableVertexAttribArray(2);
// Unbind the VAO
glBindVertexArray(0);
我的數據是:
vector<vec3> vertices, v_normals,v_color;
vector<int> vTable;
我有每個頂點的頂點,法線和顏色以及帶有每個三角形的索引頂點的索引表。
當我嘗試渲染此圖像時,窗口上沒有任何內容。
glBindVertexArray(VAO); //Bind VAO
glDrawElements(GL_TRIANGLES, vTable.size(), GL_UNSIGNED_INT, &vTable[0]);
glBindVertexArray(0); //Unbind VAO
如果我用這個:
glDrawArrays(GL_TRIANGLES,0,vTable.size());
它繪制的只是一個不完整的對象,就像在鏈接圖像中一樣。
有人知道會發生什么嗎? 提前致謝
您的glDrawElements
調用是錯誤的,最后一個參數應該是GL_ELEMENT_ARRAY_BUFFER
的字節偏移量,該偏移量保存索引,而不是指向系統內存的指針。
glDrawElements(GL_TRIANGLES, vTable.size(), GL_UNSIGNED_INT, 0);
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