在我的應用程序中,我使用OpenGL ES渲染從互聯網下載的文件,然後將文件解析爲頂點數組,因此必須在啓動後輸入頂點和法線數據。我是OpenGL ES的新手,但我一直在閱讀和學習。我已經設置了一個頂點和法線緩衝區,似乎工作正常,但我認爲我正在將頂點和法線數據錯誤地放入緩衝區,因爲當我加載視圖時,那裏有一個對象,它隱約類似於我想要的形狀但是三角形在各個方向上偏離,部分形狀缺失。這是我輸入我的數據到緩衝區代碼:iOS上的OpenGL ES向緩衝區添加頂點
for (int i = 0; i < triangle_cnt; i++) {
int base = i * 18;
GLfloat x1 = vertices[base];
GLfloat y1 = vertices[base + 1];
GLfloat z1 = vertices[base + 2];
GLfloat x2 = vertices[base + 6];
GLfloat y2 = vertices[base + 7];
GLfloat z2 = vertices[base + 8];
GLfloat x3 = vertices[base + 12];
GLfloat y3 = vertices[base + 13];
GLfloat z3 = vertices[base + 14];
vector_t normal;
vector_t U;
vector_t V;
GLfloat length;
U.x = x2 - x1;
U.y = y2 - y1;
U.z = z2 - z1;
V.x = x3 - x1;
V.y = y3 - y1;
V.z = z3 - z1;
normal.x = U.y * V.z - U.z * V.y;
normal.y = U.z * V.x - U.x * V.z;
normal.z = U.x * V.y - U.y * V.x;
length = normal.x * normal.x + normal.y * normal.y + normal.z * normal.z;
length = sqrt(length);
base = i * 9;
verticesBuff[base] = x1;
verticesBuff[base + 1] = y1;
verticesBuff[base + 2] = z1;
normalsBuff[base] = normal.x;
normalsBuff[base + 1] = normal.y;
normalsBuff[base + 2] = normal.z;
verticesBuff[base + 3] = x2;
verticesBuff[base + 4] = y2;
verticesBuff[base + 5] = z2;
normalsBuff[base + 3] = normal.x;
normalsBuff[base + 4] = normal.y;
normalsBuff[base + 5] = normal.z;
verticesBuff[base + 6] = x3;
verticesBuff[base + 7] = y3;
verticesBuff[base + 8] = z3;
normalsBuff[base + 6] = normal.x;
normalsBuff[base + 7] = normal.y;
normalsBuff[base + 8] = normal.z;
fprintf(stderr, "%ff, %ff, %ff, %ff, %ff, %ff, \n", x1, y1, z1, normal.x, normal.y, normal.z);
fprintf(stderr, "%ff, %ff, %ff, %ff, %ff, %ff, \n", x2, y2, z2, normal.x, normal.y, normal.z);
fprintf(stderr, "%ff, %ff, %ff, %ff, %ff, %ff, \n", x3, y3, z3, normal.x, normal.y, normal.z);
}
,這裏是我使用的使用這些緩衝區代碼:
- (void)setupGL {
[EAGLContext setCurrentContext:self.context];
[self loadShaders];
self.effect = [[GLKBaseEffect alloc] init];
self.effect.light0.enabled = GL_TRUE;
self.effect.light0.diffuseColor = GLKVector4Make(.05f, .55f, 1.0f, 1.0f);
glEnable(GL_DEPTH_TEST);
glGenVertexArraysOES(1, &_vertexArray);
glBindVertexArrayOES(_vertexArray);
glGenBuffers(1, &_vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, vertCount*sizeof(verticesBuff)*3*2, NULL, GL_STATIC_DRAW);
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(verticesBuff) * vertCount * 3, verticesBuff);
glBufferData(GL_ARRAY_BUFFER, vertCount*sizeof(normalsBuff)*3*2, NULL, GL_STATIC_DRAW);
glBufferSubData(GL_ARRAY_BUFFER, sizeof(GLfloat) * vertCount * 3, sizeof(normalsBuff) * vertCount * 3, normalsBuff);
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(0));
glEnableVertexAttribArray(GLKVertexAttribNormal);
glVertexAttribPointer(GLKVertexAttribNormal, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(12));
glBindVertexArrayOES(0);
_rotMatrix = GLKMatrix4Identity;
_quat = GLKQuaternionMake(0, 0, 0, 1);
_quatStart = GLKQuaternionMake(0, 0, 0, 1);
}
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {
glClearColor(0.78f, 0.78f, 0.78f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBindVertexArrayOES(_vertexArray);
// Render the object with GLKit
[self.effect prepareToDraw];
glVertexPointer(3, GL_FLOAT, 0, verticesBuff);
glNormalPointer(GL_FLOAT, 0, normalsBuff);
glDrawArrays(GL_TRIANGLES, 0, vertCount); //*******************************
// Render the object again with ES2
glUseProgram(_program);
glUniformMatrix4fv(uniforms[UNIFORM_MODELVIEWPROJECTION_MATRIX], 1, 0, _modelViewProjectionMatrix.m);
glUniformMatrix3fv(uniforms[UNIFORM_NORMAL_MATRIX], 1, 0, _normalMatrix.m);
glDrawArrays(GL_TRIANGLES, 0, vertCount);
}
如果我把這些日誌並將它們粘貼到頂點數組使用Apple在創建OpenGL ES應用程序時提供的代碼的示例應用程序,然後該對象渲染得非常漂亮,所以我推斷我必須將頂點數據放在錯誤的位置。
所以有人可以幫助我瞭解我在做什麼錯誤時輸入頂點和法線?任何幫助表示讚賞。
而且這是我的渲染看起來像:
而且這是在外形,至少,它應該是什麼樣子:
您發佈的信息太少。添加關於如何使用這些緩衝區和繪圖調用的代碼。 –
好吧,我已經添加了它。 – harryisaac