如何使用glDrawVertex（）函数在ANSI C

Question

我试图使用glDrawArrays()但我总是得到glDrawArrays呼叫段故障。难道我做错了什么？

/*MESH*/ 
struct Mesh 
{ 
GLsizei numVertices; 
GLfloat vertices[48]; 
} m; 

static void meshCreate(struct Mesh *mesh) 
{ 
mesh->vertices[0] = 0.000000f; 
mesh->vertices[1] = -0.000000f; 
mesh->vertices[2] = -0.800000f; 
mesh->vertices[3] = 0.000000f; 
mesh->vertices[4] = 0.158333f; 
mesh->vertices[5] = -0.177084f; 
mesh->vertices[6] = 0.300000f; 
mesh->vertices[7] = -0.000000f; 
mesh->vertices[8] = -0.300000f; 
mesh->vertices[9] = -0.300000f; 
mesh->vertices[10] = -0.000000f; 
mesh->vertices[11] = -0.300000f; 
mesh->vertices[12] = 0.300000f; 
mesh->vertices[13] = 0.000000f; 
mesh->vertices[14] = 0.300000f; 
mesh->vertices[15] = -0.300000f; 
mesh->vertices[16] = 0.000000f; 
mesh->vertices[17] = 0.300000f; 
mesh->vertices[18] = 0.177084f; 
mesh->vertices[19] = 0.158333f; 
mesh->vertices[20] = -0.000000f; 
mesh->vertices[21] = 0.800000f; 
mesh->vertices[22] = -0.000000f; 
mesh->vertices[23] = -0.000000f; 
mesh->vertices[24] = -0.177083f; 
mesh->vertices[25] = 0.158333f; 
mesh->vertices[26] = -0.000000f; 
mesh->vertices[27] = -0.800000f; 
mesh->vertices[28] = -0.000000f; 
mesh->vertices[29] = -0.000000f; 
mesh->vertices[30] = 0.000000f; 
mesh->vertices[31] = 0.158333f; 
mesh->vertices[32] = 0.177083f; 
mesh->vertices[33] = 0.000000f; 
mesh->vertices[34] = 0.000000f; 
mesh->vertices[35] = 0.800000f; 
mesh->vertices[36] = 0.000000f; 
mesh->vertices[37] = -0.158333f; 
mesh->vertices[38] = -0.177084f; 
mesh->vertices[39] = 0.177084f; 
mesh->vertices[40] = -0.158333f; 
mesh->vertices[41] = -0.000000f; 
mesh->vertices[42] = -0.177083f; 
mesh->vertices[43] = -0.158333f; 
mesh->vertices[44] = -0.000000f; 
mesh->vertices[45] = 0.000000f; 
mesh->vertices[46] = -0.158333f; 
mesh->vertices[47] = 0.177083f; 

mesh->numVertices = 48; 

logAdd(&gameLog, "Info: Mesh loaded."); 
} 

static void meshRender(struct Mesh *mesh) 
{ 
glVertexPointer(3, GL_FLOAT, 0, mesh->vertices); 
glDrawArrays(GL_QUADS, 0, mesh->numVertices); //<- here segmentation fault 
} 

//edit 

meshCreate(&m); //OK 
printf("%f", m.vertices[47]);//OK - variable m exists and has good values 

//begin of loop 
glClear(); 
meshRender(&m); //<-segfault 
glfwSwapBuffers(); 

Answer 1

从规格：

count : Specifies the number of indices to be rendered. 

你每索引3个坐标，所以

glDrawArrays(GL_QUADS, 0, mesh->numVertices/3)