How can I apply different shader for GraphicsOutput

C++ coding using Panda3D
1

I’m going to implement SSAO with Panda3D, so I should make depth texture in the process.

I tried to make depth texture by GraphicsOutput (used GraphicsWindow for test in under code), but I don’ t know how to apply different shader to new window.

I thought one way to apply two shader with two models, but it looks like inefficient.

How can I do it?

#include "pandaFramework.h"
#include "pandaSystem.h"
#include "texturePool.h"

int main(int argc, char *argv[])
{
	PandaFramework framework;
	framework.open_framework(argc, argv);
	framework.set_window_title("Title");

	WindowFramework *window = framework.open_window();
	NodePath render = window->get_render();

	NodePath model = window->load_model(render, "models/winged-victory");
	PT(TextureStage) tex0 = new TextureStage("tex0");
	PT(TextureStage) tex1 = new TextureStage("tex1");
	model.set_texture(tex0, TexturePool::load_texture("models/texture"));
	model.set_texture(tex1, TexturePool::load_texture("models/normal"));

	window->setup_trackball();
	window->center_trackball(model);

	PT(Shader) depShader = Shader::load(Shader::SL_GLSL, "shaders/depth.vert", "shaders/depth.frag");
	
	PT(GraphicsWindow) depBuf = window->get_graphics_window(); // ->make_texture_buffer("depBuf", 800, 600);
	PT(Texture) depTex = depBuf->get_texture();
	PT(DisplayRegion) depRegion = depBuf->make_display_region(0.8, 1, 0.8, 1);
	PT(Camera) depCam = new Camera("depCam");
	NodePath depCamNode(depCam);
	depBuf->set_sort(-1);
	depRegion->set_camera(depCamNode);
	depCamNode.reparent_to(window->get_camera_group());

	//PT(TextureStage) tex2 = new TextureStage("tex2");
	//model.set_texture(tex2, depTex);

	PT(Shader) mainShader = Shader::load(Shader::SL_GLSL, "shaders/shader.vert", "shaders/shader.frag");
	render.set_shader(mainShader);
	render.set_shader_input(~);

	framework.main_loop();
	framework.close_framework();

	return 0;
}
2

You can use the initial state of the camera to set this.

camera->set_initial_state(RenderState::make(ShaderAttrib::make(shader), 1));

Or:

NodePath state_np("");
state_np.set_shader(shader, 1);
camera->set_initial_state(state_np.get_state());
3

It works well, thanks! :smiley:

4

Ah… I find one problem on this code.

I think that main window and graphics window will return same pixel’s position, but they didn’t.

/* c++ code */

#include "pandaFramework.h"
#include "pandaSystem.h"

int main(int argc, char *argv[])
{
	PandaFramework framework;
	framework.open_framework(argc, argv);
	framework.set_window_title("?");

	WindowFramework *window = framework.open_window();
	NodePath render = window->get_render();

	NodePath model = window->load_model(render, "models/winged-victory");

	window->setup_trackball();
	window->center_trackball(model);

	PT(Shader) redShader = Shader::load(Shader::SL_GLSL, "shaders/red.vert", "shaders/red.frag");
	PT(Shader) grnShader = Shader::load(Shader::SL_GLSL, "shaders/grn.vert", "shaders/grn.frag");
	
	PT(GraphicsWindow) buf = window->get_graphics_window();
	PT(DisplayRegion) region = buf->make_display_region();
	PT(Camera) cam = new Camera("cam");
	NodePath camNode(cam);
	buf->set_sort(-1);
	region->set_camera(camNode);
	cam->set_initial_state(RenderState::make(ShaderAttrib::make(grnShader), 1));
	camNode.reparent_to(window->get_camera_group());
	
	render.set_shader(redShader);

	framework.main_loop();
	framework.close_framework();

	return 0;
}

/* vert: same for red and green */

#version 130

uniform mat4 p3d_ModelViewProjectionMatrix;

in vec4 p3d_Vertex;

void main()
{
	gl_Position = p3d_ModelViewProjectionMatrix * p3d_Vertex;
}

/* red.frag */

#version 130

void main()
{
	gl_FragColor = vec4(1, 0, 0, 1);
}

/* grn.frag */

#version 130

void main()
{
	gl_FragColor = vec4(0, 1, 0, 1);
}

O5WDetD.png?1800×600

Moreover, if I change render’s shader to grnShader, two window’s pixel positions are exactly same.

Why does it happen?

5

I’m really just guessing here, and might be totally wrong, but have you tried setting your main cameras lens on your buffer camera? If they have a different FOV for example, you will get different images. So something like that (untested):

cam->set_lens(window->get_camera(0)->get_lens());
6

It works perfectly!

Thanks for reply :smiley: