220 lines
8.5 KiB
C++
220 lines
8.5 KiB
C++
#include "pch.h"
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#include "log.h"
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#include "brush.h"
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void ui::BrushMesh::draw(const std::vector<StrokeSample>& samples, const glm::mat4& proj)
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{
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std::vector<instance_t> attributes;
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attributes.reserve(samples.size());
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for (const auto& s : samples)
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{
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auto mvp = proj *
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glm::translate(glm::vec3(s.pos, 0)) *
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glm::scale(glm::vec3(s.size, s.size, 1)) *
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glm::eulerAngleZ(s.angle);
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attributes.emplace_back(instance_t{ mvp, s.flow });
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}
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#ifdef USE_VBO
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glBindBuffer(GL_ARRAY_BUFFER, buffers[2]);
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glBufferData(GL_ARRAY_BUFFER, (int)(sizeof(instance_t) * attributes.size()), attributes.data(), GL_STATIC_DRAW);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glBindVertexArray(vao);
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glDrawElementsInstanced(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0, (int)samples.size());
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glBindVertexArray(0);
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#else
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glEnableVertexAttribArray(0);
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glEnableVertexAttribArray(1);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[1]);
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glBindBuffer(GL_ARRAY_BUFFER, buffers[0]);
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glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (GLvoid*)offsetof(vertex_t, pos));
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glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (GLvoid*)offsetof(vertex_t, uvs));
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// Likewise, we can do the same with the model matrix. Note that a
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// matrix input to the vertex shader consumes N consecutive input
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// locations, where N is the number of columns in the matrix. So...
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// we have four vertex attributes to set up.
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glBindBuffer(GL_ARRAY_BUFFER, buffers[2]);
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glBufferData(GL_ARRAY_BUFFER, (int)(sizeof(instance_t) * attributes.size()), attributes.data(), GL_STATIC_DRAW);
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// Loop over each column of the matrix...
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for (int i = 0; i < 4; i++)
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{
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// Set up the vertex attribute
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glVertexAttribPointer(loc_mvp + i, 4, GL_FLOAT, GL_FALSE, sizeof(instance_t),
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(GLvoid*)(offsetof(instance_t, mvp) + sizeof(glm::vec4) * i));
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// Enable it
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glEnableVertexAttribArray(loc_mvp + i);
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// Make it instanced
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glVertexAttribDivisor(loc_mvp + i, 1);
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}
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glEnableVertexAttribArray(loc_flow);
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glVertexAttribPointer(loc_flow, 1, GL_FLOAT, GL_FALSE, sizeof(instance_t),
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(GLvoid*)offsetof(instance_t, flow));
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glVertexAttribDivisor(loc_flow, 1);
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glDrawElementsInstanced(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0, (int)samples.size());
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//glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
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glDisableVertexAttribArray(0);
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glDisableVertexAttribArray(1);
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for (int i = 0; i < 4; i++)
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glDisableVertexAttribArray(loc_mvp + i);
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glDisableVertexAttribArray(loc_flow);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
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#endif // USE_VBO
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}
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bool ui::BrushMesh::create()
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{
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static GLushort idx[6]{ 0, 1, 2, 0, 2, 3 };
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static vertex_t vertices[4]{
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{ { -.5f, -.5f, 0, 1 }, { 0, 0 } }, // A B----C
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{ { -.5f, .5f, 0, 1 }, { 0, 1 } }, // B --\ | |
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{ { .5f, .5f, 0, 1 }, { 1, 1 } }, // C --/ | |
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{ { .5f, -.5f, 0, 1 }, { 1, 0 } }, // D A----D
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};
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glGenBuffers(3, buffers);
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if (!(buffers[0] && buffers[1] && buffers[2]))
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return false;
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static instance_t inst{ glm::mat4(), .1f };
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glBindBuffer(GL_ARRAY_BUFFER, buffers[2]);
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glBufferData(GL_ARRAY_BUFFER, sizeof(instance_t), &inst, GL_STATIC_DRAW);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[1]);
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(idx), idx, GL_STATIC_DRAW);
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glBindBuffer(GL_ARRAY_BUFFER, buffers[0]);
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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// STROKE - INSTANCED
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static const char* shader_stroke_inst_v =
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SHADER_VERSION
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"in vec4 pos;"
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"in vec2 uvs;"
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"in mat4 a_mvp;"
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"in float a_flow;"
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"out vec3 uv;"
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"out float alpha;"
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"void main(){"
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" uv = vec3(uvs, pos.w);"
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" alpha = a_flow;"
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" gl_Position = a_mvp * vec4(pos.xyz, 1.0);"
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"}";
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static const char* shader_stroke_inst_f =
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SHADER_VERSION
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"uniform mediump sampler2D tex;"
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"uniform mediump vec4 col;"
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"in mediump float alpha;"
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"in mediump vec3 uv;"
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"out mediump vec4 frag;"
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"void main(){"
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" mediump float a = (1.0 - texture(tex, uv.xy).r) * alpha;"
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" frag = vec4(col.rgb, a);"
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"}";
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if (!shader.create(shader_stroke_inst_v, shader_stroke_inst_f))
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LOG("Failed to create shader BrushMesh Stroke");
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loc_flow = shader.GetAttribLocation("a_flow");
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loc_mvp = shader.GetAttribLocation("a_mvp");
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#if USE_VBO
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glGenVertexArrays(1, &vao);
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if (!vao)
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return false;
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glBindVertexArray(vao);
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glEnableVertexAttribArray(0);
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glEnableVertexAttribArray(1);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[1]);
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glBindBuffer(GL_ARRAY_BUFFER, buffers[0]);
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glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (GLvoid*)offsetof(vertex_t, pos));
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glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (GLvoid*)offsetof(vertex_t, uvs));
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glBindBuffer(GL_ARRAY_BUFFER, buffers[2]);
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// Loop over each column of the matrix...
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for (int i = 0; i < 4; i++)
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{
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// Set up the vertex attribute
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glVertexAttribPointer(loc_mvp + i, 4, GL_FLOAT, GL_FALSE, sizeof(instance_t),
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(GLvoid*)(offsetof(instance_t, mvp) + sizeof(glm::vec4) * i));
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// Enable it
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glEnableVertexAttribArray(loc_mvp + i);
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// Make it instanced
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glVertexAttribDivisor(loc_mvp + i, 1);
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}
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glEnableVertexAttribArray(loc_flow);
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glVertexAttribPointer(loc_flow, 1, GL_FLOAT, GL_FALSE, sizeof(instance_t),
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(GLvoid*)offsetof(instance_t, flow));
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glVertexAttribDivisor(loc_flow, 1);
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glBindVertexArray(0);
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#endif
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return true;
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}
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ui::StrokeSample ui::Stroke::randomize_sample(const glm::vec2& pos, float pressure)
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{
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auto rnd_nor = [&] { return float((double)prng() / (double)prng.max()); }; // normalized [0, +1]
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//auto rnd_neg = [&] { return float((double)prng() / (double)prng.max() * 2.0 - 1.0); }; // normalized [-1, +1]
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auto rnd_rad = [&] { return float((double)prng() / (double)prng.max() * M_PI * 2.0); }; // normalized [0, 2pi]
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auto rnd_vec = [&] { float rad = rnd_rad(); return glm::vec2(cosf(rad), sinf(rad)); }; // normalized direction vector
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StrokeSample s;
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s.angle = (m_brush.m_tip_angle + rnd_nor() * m_brush.m_jitter_angle) * (float)(M_PI * 2.0);
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s.pos = pos + (rnd_vec() * m_brush.m_jitter_spread * 100.f);
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s.size = 100.f * m_brush.m_tip_size * (1.f - rnd_nor() * m_brush.m_jitter_scale);
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s.flow = m_brush.m_tip_flow * (1.f - rnd_nor() * m_brush.m_jitter_flow);
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return s;
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}
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std::vector<ui::StrokeSample> ui::Stroke::compute_samples()
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{
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if (m_keypoints.empty()) return {};
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int nsamples = (int)glm::floor((m_keypoints.back().dist - m_dist) / m_step);
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std::vector<StrokeSample> samples;
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samples.reserve(nsamples); // preallocate the estimate number of samples
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while (m_keypoints.back().dist > (m_dist + m_step))
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{
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m_dist += m_step;
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while (m_dist > m_keypoints[m_last_kp + 1].dist)
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m_last_kp++;
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const auto& A = m_keypoints[m_last_kp];
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const auto& B = m_keypoints[m_last_kp + 1]; // NOTE: this should be true when while is true
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float t = (m_dist - A.dist) / (B.dist - A.dist); // NOTE: must be A != B
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auto pos = glm::lerp(A.pos, B.pos, t);
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float pressure = glm::lerp(A.pressure, B.pressure, t);
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auto s = randomize_sample(pos, pressure);
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samples.push_back(s);
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}
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return std::move(samples);
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}
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bool ui::Stroke::has_sample()
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{
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return m_keypoints.empty() ? false : // no keypoints
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(m_keypoints.back().dist > (m_dist + m_step)); // check if next kp is closer than spacing
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}
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void ui::Stroke::reset(bool clear_keypoints /*= false*/)
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{
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m_last_kp = 0;
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m_dist = 0.f;
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if (clear_keypoints)
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m_keypoints.clear();
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}
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void ui::Stroke::add_point(glm::vec2 pos, float pressure)
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{
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float dist = m_keypoints.empty() ? 0.f :
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m_keypoints.back().dist + glm::distance(m_keypoints.back().pos, pos);
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m_keypoints.emplace_back();
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m_keypoints.back().pos = pos;
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m_keypoints.back().pressure = pressure;
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m_keypoints.back().dist = dist;
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}
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void ui::Stroke::start(const ui::Brush& brush)
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{
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m_last_kp = 0;
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m_dist = 0.f;
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m_step = glm::max(brush.m_tip_spacing * brush.m_tip_size * 30, 0.1f);
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m_brush = brush;
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prng.seed(0);
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} |