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/******************************************************************************
* The MIT License (MIT)
*
* Copyright (c) 2019-2022 Baldur Karlsson
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
******************************************************************************/
#include "gl_test.h"
RD_TEST(GL_Mip_Gen_RT, OpenGLGraphicsTest)
{
static constexpr const char *Description =
"Tests rendering from one mip to another to do a downsample chain";
std::string vertex = R"EOSHADER(
#version 420 core
out vec2 uv;
void main()
{
const vec4 verts[4] = vec4[4](vec4(-1.0, -1.0, 0.5, 1.0), vec4(1.0, -1.0, 0.5, 1.0),
vec4(-1.0, 1.0, 0.5, 1.0), vec4(1.0, 1.0, 0.5, 1.0));
gl_Position = verts[gl_VertexID];
uv = gl_Position.xy * 0.5f + 0.5f;
}
)EOSHADER";
std::string pixel = R"EOSHADER(
#version 420 core
in vec2 uv;
layout(location = 0, index = 0) out vec4 Color;
layout(binding = 0) uniform sampler2D tex2D;
void main()
{
Color = textureLod(tex2D, -uv, 0.0f);
}
)EOSHADER";
int main()
{
// initialise, create window, create context, etc
if(!Init())
return 3;
GLuint vao = MakeVAO();
glBindVertexArray(vao);
GLuint vb = MakeBuffer();
glBindBuffer(GL_ARRAY_BUFFER, vb);
glBufferStorage(GL_ARRAY_BUFFER, sizeof(DefaultTri), DefaultTri, 0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(DefaultA2V), (void *)(0));
glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(DefaultA2V), (void *)(sizeof(Vec3f)));
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(DefaultA2V),
(void *)(sizeof(Vec3f) + sizeof(Vec4f)));
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glEnableVertexAttribArray(2);
GLuint program = MakeProgram(vertex, pixel);
GLuint tex = MakeTexture();
glBindTexture(GL_TEXTURE_2D, tex);
glTexStorage2D(GL_TEXTURE_2D, 8, GL_SRGB8_ALPHA8, 1024, 1024);
GLuint fbo[8];
for(int i = 0; i < 8; i++)
{
fbo[i] = MakeFBO();
glBindFramebuffer(GL_FRAMEBUFFER, fbo[i]);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex, i);
}
// fill upper mip with colour ramp
uint32_t *ramp = new uint32_t[1024 * 1024];
for(uint32_t i = 0; i < 1024 * 1024; i++)
{
float x = float(i % 1024);
float y = float(i / 1024);
ramp[i] = uint32_t(uint32_t(255.0f * (x / 1024.0f)) | (uint32_t(255.0f * (y / 1024.0f)) << 8) |
(uint32_t(255.0f * ((x + y) / 2048.0f)) << 16) | 0xff000000);
}
while(Running())
{
float col[] = {0.2f, 0.2f, 0.2f, 1.0f};
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glClearBufferfv(GL_COLOR, 0, col);
// clear all FBOs
for(int i = 0; i < 8; i++)
{
glBindFramebuffer(GL_FRAMEBUFFER, fbo[i]);
glClearBufferfv(GL_COLOR, 0, col);
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindVertexArray(vao);
glUseProgram(program);
{
// view first mip and upload data
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 1024, 1024, GL_RGBA, GL_UNSIGNED_BYTE, ramp);
for(int i = 1; i < 8; i++)
{
// bind relevant fbo
glBindFramebuffer(GL_FRAMEBUFFER, fbo[i]);
// change texture parameters to view previous mip
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, i - 1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, i - 1);
// set viewport
glViewport(0, 0, 1024 >> i, 1024 >> i);
// do downsample
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}
// reset texture parameters to default
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
// bind default framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
Present();
}
delete[] ramp;
return 0;
}
};
REGISTER_TEST();
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