我无法弄清楚如何使用屏幕坐标在我的场景中定位2D对象。目前我有一些工作(下面的代码),但它想要NDC坐标,这是不容易使用的。我无法弄清楚它出了什么问题。我想我已经习惯了应有的一切,所以我觉得我忘了什么。
这是处理场景中对象绘制的代码:
getContext().getResources()
其中colorProgram是我的精灵使用的着色器,glClearDepth(1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// RENDERING HERE
colorProgram.bind();
for (size_t t = 0; t < objectsWithGraphicsComponentInThisScene.size(); ++t)
{
// set texture
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, objectsWithGraphicsComponentInThisScene[t]->getComponent<GraphicsComponent>()->getTexture());
GLint texLocation = colorProgram.getUniformLocation("texSampler");
glUniform1i(texLocation, 0);
glm::mat4 trans;
trans = glm::translate(glm::mat4x4(1.0f), glm::vec3(objectsWithGraphicsComponentInThisScene[t]->getPosition().x, objectsWithGraphicsComponentInThisScene[t]->getPosition().y, 0));
GLint transMatLocation = colorProgram.getUniformLocation("transformMatrix");
glUniformMatrix4fv(transMatLocation, 1, GL_FALSE, glm::value_ptr(trans));
// set camera Matrix
GLint projMatLocation = colorProgram.getUniformLocation("projectionMatrix");
glm::mat4 cameraMatrix = camera->getCameraMatrix();
glUniformMatrix4fv(projMatLocation, 1, GL_FALSE, glm::value_ptr(cameraMatrix));
objectsWithGraphicsComponentInThisScene[t]->getComponent<GraphicsComponent>()->getSprite()->draw();
// unbind all
glBindTexture(GL_TEXTURE_2D, 0);
}
colorProgram.unbind();
只返回我设置的值。 (其中x y和z值应作为屏幕坐标给出)。例如,getPosition可能会返回[100,50,0],但这会将对象渲染到屏幕之外(屏幕为1280x720)。
现在呈现精灵的代码(objectsWithGraphicsComponentInThisScene [t] - &gt; getComponent() - &gt; getSprite() - &gt; draw();):
getPosition()
以下是着色器中的代码(colorProgram): VERTEX SHADER:
void Sprite::draw()
{
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glEnableVertexAttribArray(0);
// position
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, position));
//color
glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(Vertex), (void*)offsetof(Vertex, color));
// uv
glVertexAttribPointer(2, 2, GL_FLOAT, GL_TRUE, sizeof(Vertex), (void*)offsetof(Vertex, uv));
glDrawArrays(GL_TRIANGLES, 0, 6);
glDisableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
FRAGMENT SHADER
#version 130
// per vertex
// input data from VBO
in vec2 vertexPosition;
in vec4 vertexColor;
in vec2 vertexUV;
// output to fragment shader
out vec4 fragmentColor;
out vec2 fragmentUV;
uniform mat4 projectionMatrix;
uniform mat4 transformMatrix;
void main()
{
mat4 resultMatrix = transformMatrix * projectionMatrix;
gl_Position.xy = (resultMatrix * vec4(vertexPosition, 0.0, 1.0)).xy;
gl_Position.z = 0.0;
// Indicate that the coordinates are normalized
gl_Position.w = 1.0;
fragmentColor = vertexColor;
fragmentUV = vec2(vertexUV.x, 1.0 - vertexUV.y);
}
如果您需要更多代码,我很乐意添加更多代码,尽管我认为这是所需的一切。