Celestia

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//
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// viewporteffect.cpp
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//
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// Copyright © 2020 Celestia Development Team. All rights reserved.
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your option) any later version.
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#include <array>
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#include "viewporteffect.h"
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#include "framebuffer.h"
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#include "render.h"
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#include "shadermanager.h"
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#include "mapmanager.h"
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namespace gl = celestia::gl;
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namespace util = celestia::util;
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static const Renderer::PipelineState ps;
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bool ViewportEffect::preprocess(Renderer* renderer, FramebufferObject* fbo)
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{
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    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &oldFboId);
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    return fbo->bind();
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}
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bool ViewportEffect::prerender(Renderer* renderer, FramebufferObject* fbo)
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{
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    if (!fbo->unbind(oldFboId))
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        return false;
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    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
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    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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    return true;
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}
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bool ViewportEffect::distortXY(float &x, float &y)
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{
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    return true;
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}
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PassthroughViewportEffect::PassthroughViewportEffect() :
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    ViewportEffect()
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{
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}
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bool PassthroughViewportEffect::render(Renderer* renderer, FramebufferObject* fbo, int width, int height)
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{
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    auto *prog = renderer->getShaderManager().getShader("passthrough");
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    if (prog == nullptr)
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        return false;
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    initialize();
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    prog->use();
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    prog->samplerParam("tex") = 0;
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    glBindTexture(GL_TEXTURE_2D, fbo->colorTexture());
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    renderer->setPipelineState(ps);
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    vo.draw();
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    glBindTexture(GL_TEXTURE_2D, 0);
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    return true;
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}
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void PassthroughViewportEffect::initialize()
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{
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    if (initialized)
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        return;
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    initialized = true;
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    static std::array quadVertices = {
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        // positions   // texCoords
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        -1.0f,  1.0f,  0.0f, 1.0f,
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        -1.0f, -1.0f,  0.0f, 0.0f,
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         1.0f, -1.0f,  1.0f, 0.0f,
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        -1.0f,  1.0f,  0.0f, 1.0f,
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         1.0f, -1.0f,  1.0f, 0.0f,
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         1.0f,  1.0f,  1.0f, 1.0f
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    };
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    vo = gl::VertexObject();
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    bo = gl::Buffer(gl::Buffer::TargetHint::Array, quadVertices, gl::Buffer::BufferUsage::StaticDraw);
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    vo.setCount(6);
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    vo.addVertexBuffer(
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        bo,
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        CelestiaGLProgram::VertexCoordAttributeIndex,
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        2,
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        gl::VertexObject::DataType::Float,
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        false,
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        4 * sizeof(float),
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        0);
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    vo.addVertexBuffer(
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        bo,
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        CelestiaGLProgram::TextureCoord0AttributeIndex,
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        2,
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        gl::VertexObject::DataType::Float,
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        false,
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        4 * sizeof(float),
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        2 * sizeof(float));
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}
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WarpMeshViewportEffect::WarpMeshViewportEffect(WarpMesh *mesh) :
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    ViewportEffect(),
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    mesh(mesh)
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{
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}
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bool WarpMeshViewportEffect::prerender(Renderer* renderer, FramebufferObject* fbo)
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{
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    if (mesh == nullptr)
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        return false;
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    return ViewportEffect::prerender(renderer, fbo);
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}
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bool WarpMeshViewportEffect::render(Renderer* renderer, FramebufferObject* fbo, int width, int height)
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{
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    auto *prog = renderer->getShaderManager().getShader("warpmesh");
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    if (prog == nullptr)
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        return false;
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    initialize();
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    prog->use();
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    prog->samplerParam("tex") = 0;
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    prog->floatParam("screenRatio") = (float)height / width;
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    glBindTexture(GL_TEXTURE_2D, fbo->colorTexture());
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    renderer->setPipelineState(ps);
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    vo.draw();
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    glBindTexture(GL_TEXTURE_2D, 0);
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    return true;
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}
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void WarpMeshViewportEffect::initialize()
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{
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    if (initialized)
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        return;
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    initialized = true;
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    vo = gl::VertexObject();
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    bo = gl::Buffer();
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    bo.setData(mesh->scopedDataForRendering(), gl::Buffer::BufferUsage::StaticDraw);
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    vo.setCount(mesh->count());
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    vo.addVertexBuffer(
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        bo,
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        CelestiaGLProgram::VertexCoordAttributeIndex,
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        2,
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        gl::VertexObject::DataType::Float,
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        false,
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        5 * sizeof(float),
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        0);
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    vo.addVertexBuffer(
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        bo,
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        CelestiaGLProgram::TextureCoord0AttributeIndex,
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        2,
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        gl::VertexObject::DataType::Float,
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        false,
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        5 * sizeof(float),
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        2 * sizeof(float));
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    vo.addVertexBuffer(
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        bo,
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        CelestiaGLProgram::IntensityAttributeIndex,
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        1,
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        gl::VertexObject::DataType::Float,
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        false,
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        5 * sizeof(float),
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        4 * sizeof(float));
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}
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bool WarpMeshViewportEffect::distortXY(float &x, float &y)
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{
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    if (mesh == nullptr)
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        return false;
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    float u;
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    float v;
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    if (!mesh->mapVertex(x * 2.0f, y * 2.0f, &u, &v))
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        return false;
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    x = u / 2.0f;
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    y = v / 2.0f;
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    return true;
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}
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