Debug No3 multi texture overlay

2022 year 7 month 17 Japan In the morning 9 Half past six

After realizing the application of single texture , Want to practice , Multiple texture overlay combinations .

1.bug state ： There are some prompts and errors on the console

analysis ： This part of the code implementation is incomplete , No texture cells are set to get values .

2.bug state ：location I can't get it shader programmatic ID, But these two methods are all right in theory （1） Will get ID Methods , Encapsulated into Shader Member methods of class   （2) adopt Shader class , Get member variable ID

analysis ： Method （1） The idea of partial encapsulation vec4(vec3,1.0)  But put glUniform1i It's a mistake glUniforml1.

            Method （2） Because make class members private , So it's not accessible .

                            In addition, this exposes Shader Of ID Information , Not a good way .

solve ： check dos.gl Look up the documents , The parameters of the lower function are studied .ID Is to call the Shader Handle to the program . On the premise that there is no problem with the theory , The analysis should focus on errors . And go to the blog to find relevant solutions , It's a waste of time . The information is not accurate enough .

3.bug state ： Two textures in the fragment shader and in the main function call , Different names , Another binary coordinate and a quaternion coordinate cannot be processed correspondingly .

analysis ： The fragment shader program is an argument , And the main function is also an argument , Keep the parameters uniform . Although the methods and steps of importing two textures and one texture are similar , But the treatment is different , You need to set the texture unit , Consider the stacking order, texture wrapping, and so on .

4.bug state ： Only one texture is displayed , Non superimposed effect .

analysis ： Picture reading problem , Break point debugging , Read successful , exclude . So I guess the first picture may be covered . Try deleting a picture , It always shows the second , determine bug reason .

solve ： Two pictures cannot be read continuously , You need to bind the first one before reading the second . reason ： Because two pictures use a pointer , There is a call order problem .

summary ： I'm looking for it today Bug It took nearly two hours . Wasted on and OpenGL Document comparison , I should improve my reading ability of code framework . Realize by yourself first , Then compare the idea of source code .

in addition , Also found when solving problems Not targeted , If it works in theory , Actually looking for bug It's easier . One is grammar , One is whether the steps are complete . When correcting mistakes, don't think too widely . One way doesn't work , Don't try again and again aimlessly .

Learning methods ： Code comes first . Theory is auxiliary . No concept of words , Only solve practical problems . Daily correspondence OpenGL Complete the exercise of .