Changing model fragment shader(android opengl es)

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• kudo(Staff)

  November 2021

  Hello, @catCoder
  Thank you for your contact.
  This is Live2D Support.
  
  Please check CubismRenderer_OpenGLES2.cpp in CubismSdkForNative Framework.
  It defines a fragment shader around which the FragShaderSrc variable is defined.
  Please follow that description and add a shader with color and effect processing.
  
  After adding the shaders, load them with the CubismShader_OpenGLES2::GenerateShaders function.
  Please replace the items that set the shaders for each application in the CubismShader_OpenGLES2::SetupShaderProgram function.
  
  hope that helps!

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• catCoder

  November 2021

  I read the code and from what I understood adding a new shader to CubismRenderer_OpenGLES2 will change all the models in the application with that shader.
  How do I add a new shader only for specific model/s in the app?
  (please excuse me I am new to the subject of Opengl es).

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• kudo(Staff)

  November 2021

  Hi, @catCoder
  
  As a prerequisite, the shaders are designed to be the same for all models.
  
  If you want to set a different shader for a specific model, you need to get the CubismModel using the CubismShader_OpenGLES2::SetupShaderProgram function.
  Please use the model information to identify your model and switch the shader to be set.
  
  hope that helps!

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• catCoder

  November 2021 edited November 2021

  I was able to pass the model name and filter for the shader I want for a specific model.
  I now face a different problem I try to add phong light to the shader but I don't understand how to calculate the normals for the model vertex positions
  can you explain the line in the SetupShaderProgram() method:
  
  glVertexAttribPointer(shaderSet->AttributePositionLocation, 2, GL_FLOAT, GL_FALSE, sizeof(csmFloat32) * 2, vertexArray);
  
  from what I think the vertexArray hold vec2 positions with stride Length of 2.
  if so what is stored in the other positions of the vertexArray?

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• kudo(Staff)

  December 2021

  Hello, @catCoder
  
  glVertexAttribPointer() is a method provided by OpenGL, so please refer to the official OpenGL documentation.
  
  The arguments are as follows.
  shaderSet->AttributePositionLocation is the index of the shader
  vertexArray is the model's vertex array obtained using csmGetDrawableVertexPositions().
  
  hope that helps!

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