我试图制作一个在Android Studio中使用NDK和JNI绘制图像的应用程序，使用OpenGL ES调用C ++代码。我已经完成了教程如何在OpenGL中执行此操作：https://learnopengl.com/#!Getting-started/Textures，它使用GLSL 330核心。但是，Android模拟器不支持OpenGL ES 3.0（请注意此链接：https://developer.android.com/ndk/guides/stable_apis.html）。
因此，我必须使用GLSL ES #version 100，它不支持＆＃34; layout＆＃34;，＆＃34; in＆＃34;和＆＃34; out＆＃34;在下面的着色器中。如何编辑它们以便它们可以在#version 100中运行，如果我编辑它们，源代码是否有任何变化？感谢您的关注和帮助。
更新：在搜索之后，我发现我可以使用glGetAttributeLocation来获取顶点着色器中变量的位置，而不是使用布局（位置= 0）。但是，在GLSL ES #version 100中没有VAO，所以如果没有VAO，我仍然无法确定其工作方式。
我的顶点着色器：
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 color;
layout (location = 2) in vec2 texCoord;
out vec3 ourColor;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(position, 1.0f);
ourColor = color;
// We swap the y-axis by substracing our coordinates from 1. This is done because most images have the top y-axis inversed with OpenGL's top y-axis.
// TexCoord = texCoord;
TexCoord = vec2(texCoord.x, 1.0 - texCoord.y);
}
片段着色器：
#version 330 core
in vec3 ourColor;
in vec2 TexCoord;
out vec4 color;
// Texture samplers
uniform sampler2D ourTexture1;
uniform sampler2D ourTexture2;
void main()
{
// Linearly interpolate between both textures (second texture is only slightly combined)
color = mix(texture(ourTexture1, TexCoord), texture(ourTexture2, TexCoord), 0.2);
}
初始化VAO，VBO，：
// Set up vertex data (and buffer(s)) and attribute pointers
GLfloat vertices[] = {
// Positions // Colors // Texture Coords
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // Top Right
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // Bottom Right
-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // Bottom Left
-0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f // Top Left
};
GLuint indices[] = { // Note that we start from 0!
0, 1, 3, // First Triangle
1, 2, 3 // Second Triangle
};
GLuint VBO, VAO, ;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, );
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
// Position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
// Color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
// TexCoord attribute
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
glBindVertexArray(0); // Unbind VAO
画一幅图像：
// Clear the colorbuffer
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Activate shader
ourShader.Use();
// Bind Textures using texture units
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture1);
glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture1"), 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, texture2);
glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture2"), 1);
// Draw container
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
答案 0 :(得分：1)
最后，我设法解决它。在GLSL ES 100中，如上所述，没有in out和layout(location=0)。因此，我必须更换它们：
in =＆gt; attribute
out =＆gt; varying
完全删除layout(location=0)，因为就我所知，在GLSL ES 100中没有同样的事情。
由于删除了layout(location=0)，我们必须告诉程序我们的顶点数据的位置，位置，颜色和 textCoord 在这种情况下。使用layout(location=0)，我们可以简单地将位置0放在
glVertexAttribPointer(0,3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
没有它，我们首先需要获取顶点属性的位置：
GLint mPosition= glGetAttributeLocation(ourProgram,"position")
然后用我预定义的mPosition：
glVertexAttribPointer(mPosition,3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(mPosition);;
color和textCoord上的内容相同。
下面是我编辑的顶点着色器，片段着色器以及如何初始化VBO并传入我们的数据：
为GLSL ES 100编辑vertex shader：
auto gVertexShader =
"attribute vec3 position;\n"
"attribute vec3 color;\n"
"attribute vec2 texCoord;\n"
"varying vec3 ourColor;\n"
"varying vec2 TexCoord;\n"
"void main()\n"
"{\n"
"gl_Position = vec4(position,1.0); // Add the xOffset to the x position of the vertex position\n"
"ourColor = color;\n"
"TexCoord= vec2(texCoord.x,1.0-texCoord.y);\n"
"}\n";
为GLSL ES 100编辑fragment shader：
static const char FRAGMENT_SHADER[] =
"#version 100\n"
"precision mediump float;\n"
"varying vec4 vColor;\n"
"void main() {\n"
" gl_FragColor = vColor;\n"
"}\n";
我的InitBuffer功能：
// Set up vertex data (and buffer(s)) and attribute pointers
GLfloat vertices[] = {
// Positions // Colors // Texture Coords
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // Top Right
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // Bottom Right
-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // Bottom Left
-0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f // Top Left
};
GLuint indices[] = { // Note that we start from 0!
0, 1, 3, // First Triangle
1, 2, 3 // Second Triangle
};
void initBuffers()
{
GLint mPosition,mCorlor,mTextCoord;
GLuint VBOs[2]; // Initialize an buffer to store all the verticles and transfer them to the GPU
glGenBuffers(2, VBOs); // Generate VBO
glBindBuffer(GL_ARRAY_BUFFER, VBOs[0]);//Bind verticles array for OpenGL to use
glBufferData(GL_ARRAY_BUFFER, sizeof(recVertices), recVertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, VBOs[1]);//Bind the indices for information about drawing sequence
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
// 1. set the vertex attributes pointers
// Position Attribute
mPosition=glGetAttributeLocation(Program, "position");
glVertexAttribPointer(mPosition, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(mPosition);
// Color Attribute
mColor=glGetAttributeLocation(Program, "color");
glVertexAttribPointer(mColor, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(mColor);
//Texture Coordinate Attribute
mTextCoord=glGetAttributeLocation(Program, "textCoord")'
glVertexAttribPointer(mTextCoord, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(mTextCoord);
}
然后我们使用initBuffer()函数
// Clear the colorbuffer
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Activate shader
ourShader.Use();
// Bind Textures using texture units
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture1);
glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture1"), 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, texture2);
glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture2"), 1);
// Draw container
initBuffers();
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
希望这能帮助那些与我有同样问题的人。如果您有任何疑问，请随时问我。）。